Sudden drop in transfer speed

I have been trying out a WRT1900AC router for about a week and just developed a MAJOR drop in speed from the router to the computer while doing a file transfer:
This thing has been sending files to and from the router's esata and USB3 port at over 50 MB/s until just now.
I can still write to the drives attached to the router at 50MB/s + all day long. Getting files from the drives have suddenly dropped to 300Kb/s on the esata and the USB3 ports
Tried rebooting/powercycling the router, disconnected the drives and reconnected them, same result.
Anyone else run into this?
Funny, I just got done posting in another thread how fast this thing moved files to and from external storage. Now this,,,,,,
Maybe the universe is telling me not to keep this router?

1. What file sizes do you usually transfer? What are the file types?
For testing I used larger files (IE: ISO files, larger zipped files, etc.) rather than just copying folders or small files.
2. Are the files being transferred to and from your computer and a storage drive (hooked to the WRT1900AC)?
Files were moved all over: from a WD Mycloud (hooked up to 8 port gigabit netgear switch) to my computer. Also have a Toshiba 1TB USB3 drive plugged into the WRT1900AC USB3 port and an older WD 2 x1TB enclosure hooked into the WRT1900AC via the eSATA port. For testing I moved files all over the place: From the Esata to the computer, to the USB drive, to the WD Mycloud and back again. Also mixed up going from point A to B, then from point C to point B, etc. In all cases the slowest speed I get is 50MB/s + with some transfers topping out at 90MB/s!!!
3. If it's a storage drive, does it have USB3 ports as well?
Yes
4. What is the link speed of your computer?
Wired Gigalan
Routers do not usually need to be rebooted every now and then. They should be running 24/7. My guess is, the wired or wireless adapter may have adjusted speeds consequently dropping file transfer speeds.
Agreed. I can count on one hand how many times I had to reboot my last router over the 2+ years I had it.
Heres the other thing: the need to reboot is not just associated with file transfers. I get the "cant connect with the WRT1900AC" message just going into the user interface from time to time as well as being unable to see storage folders in Windows explorer from time to time. In these cases I can still go online, surfing and doing whatever. The router (according to the Smartlink page) just seems to disappear. Which doesnt make sense since if the router cant be seen online, how is it that I can still go online?
Anywho, I still have this week before I lose the ability to return/exchange it at Best Buy. Will see how things go.
And thanks for the reply and suggestions,,,,,,,,,,

Similar Messages

Please help cure sudden drop in BB speed

Hi,
Following the advice of a BT Openreach engineer I recently installed a new Home Hub 3 modem - the engineer was upgrading my old phone socket to a new 'dual' ADSL/Phone socket and installing new cabling to the telegraph pole outside our property).
Initially I was getting very good BB speeds (for this area) of around 4-5 Mbps however a week ago the speed dropped overnight to about 1.8 Mbps, with many web pages taking significantly longer to load - ironically BT pages seem to take the longest now.
I reset the modem with the hope that the speed may pick up again but 5 days on and the speed is still only around 1.93 Mbps. I ran the BT Speed Test using the following computers (one at a time) connected directly via ethernet cable to either the HH3 GigE socket or the regular Ethernet socket:
MacBook Pro
Samsung Notebook
MacBook Air
iMac
Mac Pro
I also ran the same test using WiFi to include iPad and iPhone - same speed results. Nothing else was connected at the time of the tests, not even the phone.
It seems the problem isn't my computers but the modem as the speed coming into it from the exchange is pretty high - 7.26 Mbps.
Any help or advice on how to get my BB speed back to what it was previously would be greatly appreciated.
Chris
my speed test results:
ADSL Line Status
Connection Information
Line state: Connected
Connection time: 5 days, 16:22:50
Downstream: 7.094 Mbps
Upstream: 448 Kbps
ADSL Settings
VPI/VCI: 0/38
Type: PPPoA
Modulation: G.992.1 Annex A
Latency type: Fast
Noise margin (Down/Up): 6.2 dB / 22.0 dB
Line attenuation (Down/Up): 34.7 dB / 20.0 dB
Output power (Down/Up): 19.8 dBm / 11.9 dBm
FEC Events (Down/Up): 0 / 3
CRC Events (Down/Up): 6981 / 64
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 0 / 0
Loss of Power (Local/Remote): 0 / 0
HEC Events (Down/Up): 9513 / 0
Error Seconds (Local/Remote): 5959 / 50
Download speed achieved during the test was - 1.93 Mbps
For your connection, the acceptable range of speeds is 0.4 Mbps-2 Mbps.
And these are the speedtester.bt.com results:
Your DSL Connection Rate :7.26 Mbps(DOWN-STREAM), 0.45 Mbps(UP-STREAM)
IP Profile for your line is - 2 Mbps
Solved!
Go to Solution.

Welcome to this forum.
Your IP profile is stuck at 2Mbs.
If you would like to contact one of the UK based BT Care Team who moderate this forum, they should be able to reset it for you.
They can be contacted using this link BT Care Team
They normally respond by phone or e-mail, within three working days, however you should get an immediate confirmation, with a tracking number.
There are some useful help pages here, for BT Broadband customers only, on my personal website.
BT Broadband customers - help with broadband, WiFi, networking, e-mail and phones.

Sudden Drop in broadband speed, Used to get 300-40...

I have been having prblems for the last 3 or 4 days now with my download speed just being so slow its becoming unusable... I work from home so need a solid internet connection to work form. I have spoken to BT that gave me the biggest load or rubbish i think i have ever heard and put the blame on my router.
So - I got rid of the HomeHub2 it was causing so much trouble with my VPN's into Work and not opening ports correctly. and i had it replaced with a NetGear DGND3300 - This has been working fine for 6 months or so without so much as a network drop or glitch and has all the right port access for me for work.
My netgear router is displaying back the following stats.
System Up Time 12:31:59
Port
Status
TxPkts
RxPkts
Collisions
Tx B/s
Rx B/s
Up Time
WAN
PPPoE
2170851
3341131
0
3516
48666
12:31:31
LAN
10M/100M
3317014
2214708
0
47139
5296
12:31:55
WLAN
11M/54M/300M
127606
63760
0
2926
156
12:31:40
ADSL Link
Downstream
Upstream
Connection Speed
3776 kbps
448 kbps
Line Attenuation
52.0 db
28.5 db
Noise Margin
13.2 db
17.0 db
Now I would normally donwload at between 300-400 Kb's but for the last few days I am getting a maximum of 20-25 Kb's which is frustrating to say the least.
I have done all the normal things, I rebooted my netgear router, I put my BtHomeHub2 back in, I replaced the filter, I have turned off every device in the house and used an ethernet cable direct to the router from my laptop and still got exactly the same speeds. So has anyone got any ideas? as BT support are just telling me its my Netgear router that is at fault. Even though I am still running off the BtHomeHub2 with the same problems.

Welcome to this customer to customer forum.
To enable forum members to help you, could you please read the web page that is shown below, which asks you to do a few checks first, and has some helpful hints.
Please could you use the home hub 2, as its not possible to extract all of the information from the Netgear router.
When you have done that, please follow the instructions at the end, and post the results here, so members can offer advice. Thank you.
Speed and disconnections
There are some useful help pages here, for BT Broadband customers only, on my personal website.
BT Broadband customers - help with broadband, WiFi, networking, e-mail and phones.

Re: Sudden Drop in Broadband Speed and problems wi...

I am having exactly the same problem. Since the 28th my speeds have gone down from 2 - 2.5 mbps to 0.1 - 0.3 mbps. It's awful and I can barely do anything.

I have moved your post and started a new subject to avoid replies for the other subject originator getting confused with replies to you
welcome to the BT community forum where customers help customers and only BT employees are the forum mods
in order for the forum members to help please can you post the adsl stats from your router may need to 'show detail' to get all stats (if hub enter 192.168.1.254 in your browser and navigate to adsl or use a-z, if netgear enter 192.168.0.1) and run btspeedtester (MAC users may have problems) bt speedtester and post the results .
are you connected directly via a filter to the NTE5 master or test socket or to somewhere else? Is the master the only phone socket in your home?
Have you tried the quiet line test? - dial 17070 option 2 - should hear nothing - best done with a corded phone. if cordless phone you may hear a 'dull hum' which is normal
Someone may then be able to offer help/assistance/suggestions to your problem
If you like a post, or want to say thanks for a helpful answer, please click on the Ratings star on the left-hand side of the post.
If someone answers your question correctly please let other members know by clicking on ’Mark as Accepted Solution’.

Major sudden drop in infinity speed - bt issue???

Is anyone else having problems? I am on Ingrebourne exchange and just noticed my download speed has collapsed. Getting between 0.5 and 2 megabits. Upload seems unaffected at 9 mbits. Usually pull 36 megabits download speed so I assume some outage with BT. Although service status shows no issues , at least not yet!
Cheers
Wayne

It's back to normal now. Must of been BT fiddling

Sudden drop in download speed and increase in uplo...

I have seen a number of discussions on this on the forum but they all seem to just fade with no resolution.
I have HH3 with Infinity and up to about 4 weeks ago I was delighted with it. Consistent 21Mbps download and 6Mbps upload. Then one afternoon the speeds just went sillly - download went down to about 6Mbps and upload to about 10Mbps. It's been more or less like that ever since.
It's wireless so thought there must be some interference somewhere. I've installed inSSIDer 3 to check for other router interference and there isn't any (I'm the only one on channel 6). I've restarted everything a number of times and given it weeks to pace. I've switched off everything that uses the router and even sat right next to it but all to no avail. The speeds just won't budge from these new low speeds. I've ethernet attached and run tests and it looks fine - 53.5Mbps upload which is great. So the problem is somewhere between coming into the house and my laptop. I thought it might be a problem with my wireless adapter but the problem is the same on another couple of laptops and a desktop. Even the iPod has slowed down.
I have found an uknown device on the wireless and every time I delete it it just comes back but I did manage to remove it for a few minutes - enough time to run the test - and the speed problem was stilll there. I've looked at entries for this strange uknown device but as I said above, the discussion just dwindled into nothing without resolution. I tried the sugggestion to limit access to the internet for this device but it didn't seem to help. It may be a red herring anyway although the mac address doesn't seem to match anything in my house. An internal device to the router maybe?
Anyway - I'm getting more and more frustrated as I've seen what speed is possible and I want it back !!!
So - any help would be hugely appreciated

Sorry - yep I meant download. I was in a bit of a hurry and went off piste.
I have been so close to the router with my laptop that I could have rested it on the router. However, I will go round one more time to see if there is something that we started when it all went wrong such as a new device of some kind. Clutching at straws but worth a try. It might be that an old device has gone bad so I'll do what I can with those (switching things off).
yep rebooted router a couple of times and allowed a few weeks for it to settle.
inSSIDer shows strength fluctuating between -48 and 50 although I dimly recall that it was -42 when I was getting the good speeds. Hub claims 130Mbps and device claims 54Mbps.
If all of that fails to work I'lll try resetting to factory settings. It just seems odd that one minute it's fine then the next it just goes into snail mode.
Thanks for the sugggestions - very welcome ...

WRT350N - Transfer speed via Storage link

I have always been curious what the transfer speed others get while using
a USB 2.0 hard drives on their WRT350N.
Obviously there is going to be a drop in transfer speed using storage link but 2-3 Megabyte seems slower then I would expect. I don't thnk I have ever seen much about 3MB.
I see the same performance wirelessly (connected at 270mb) and hardwired into the gig ethernet port.
Just wanted to get some other peoples results.
Message Edited by GAH1068 on 01-17-2008 02:04 PM

It was on both systems. However, I did get it working. Not the way I liked, but it works. What I expected to see was the device hung off the network. That is like another computer. This *is* happening, but where I was confused was the access to it. On other shared resources I can open it at will with no special access rights needed. I'm talking about printers and files on other computers on the network. It turned out to access the Storage Link I had to actually provide a USER ID and PASSWORD before I could use it. Why I couldn't get access before was I had HTTP:\\192.168.1.1 already open in my browser so any other attempts via the web browser used the existing connection. Not until I saw a forum message that said use START=>RUN and enter the IP address or UNC name was I able to connect to it. Since I now know this, a simple bat file with some NET USE's should fix the problem of getting access. Compounding my problem is how I've chosen to manage the network and shares. I use Network Magic, and it can NOT see the Storage Link at all. Anyway, I now know how to access the Storage Link. I was using a Flash drive for testing. I'll next put a USB External drive on and try that out. My ultimate try will be a USB hub and 4 external drives and hopefully I'll have access to all 4 drives to all computers. Irv S.
Thanks,
Irv S.

BT Inifinity - Speed and Latency - Sudden Drop in ...

Hi All,
I hope someone can help me here, I'm really just looking for some advice and an opinion. I have had BT Infiinity for around a year now, and, barring the first few weeks, i have had a stable connection of around 68000kbps down (sync) and 20000kbps up (sync), with a usually low ping of around 5ms to most UK Servers.
The last few weeks i have had a sudden drop in sync to around 54000kbps, showing attainable as 62000kbps, up speed has also dropped a few meg. to top this off, the interleaving depth has gone from a solid fast-path that i used to have, and was completely stable. to a depth of 1050 (down), up is strangely still on fast-path though.
do you think i have a line fault or is something effecting noise on my line? The biggest bug bear for me about this is the latency, as I am an an avid online gamer, when I'm not working or entertaining my 1 year old son.
Before i even touch a gaming server, i seem to have a ping of around 20-35ms, which as other gamers will know, is not good.
i have included a few graphs for the ones who know more about VDSL than i do, as my FEC errors seem unusually high.
Thanks in advance peeps :-)

Hi john014,
Thanks for posting. Have you tried the quiet line test? Dial 17070 option 2, it should be quiet but if you’re getting any noise on the line we’ll need to look into that for you.
If it’s all clear can you try posting a few tracerts i.e. one to the game and one to the BC site for comparison. I’m sure we can help with this.
Cheers
David
BTCare Community Mod
If we have asked you to email us with your details, please make sure you are logged in to the forum, otherwise you will not be able to see our ‘Contact Us’ link within our profiles.
We are sorry but we are unable to deal with service/account queries via the private message(PM) function so please don't PM your account info, we need to deal with this via our email account :-)

FileSharing Transfer Speed Drops after sharing internet connection

Hi Folks
Sometimes, when I copy files via FileSharing,
the speed drops exactly to the max. upload speed my internet connection has.
= instead of 12 MB/s I got 600 ~700 KB/s.
I needed a bit of work to see this connection.
But after a while, it changes back to normal.
However, I did share the ethernet-internet-connection from one machine via WiFi (to surf with an iPod Touch).
Could that initiate this problem? I believe so.
Internet-Provider is cablecom, switzerland, zurich.
I use a Zyxel Ethernet Switch to connect two macs with the cablecom-modem (and together).
So Idetached the cablecom-modem from the ZyXel Switch and restarted both machines.
Now, the copy-action via filesharing has the expected full speed. (Just no internet, of course).
After that I connected the Cablecom-Modem again,
restarted (PowerOff/On) the ZyXel Switch,
and tried the same again:
Now the speed is slow.
It seems that I really should NOT share the Ethernet Internet Connection with WiFi
Won't do that anymore because I often copy files from one machine to the other and this slow transfer speed kills me.
Why is that affecting the connection between two local machines?
How can I reset this to "normal".
I hope there is a way to do it in OS X instead of waiting until it sets itself to "normal" from cablecom's side.
[ -Despite the fact that I should use a wireless router- ]
Is there any chance that this is an issue that OS X could resolve?
Best would probably be: the local connection between two machines should not be affected by the provider in any circumstances.
BTW: The cablecom-modem gives - via a ZyXel Switch - both computers unique IP's and they are reachable/visible from the internet.
Greetings from Zurich
Alain Burki
If my English is bad
please forgive me

I am doing the same thing (have tried it occasionally over the past 6 months or so and cannot install Arch because of it)...sad panda. The downloads start fast (up to 5MB/s), then when it gets to 49% it slows all the way down until it gives up and moves to the next mirror, repeating and repeating and repeating until finally it shows:
core is up to date
error: failed to update extra (download library error)
error: failed to update community (download library error)
:: There are 51 members in group base
:: Repository core
Enter a selection (default=all): error: failed to prepare transaction (could not find database)
I've tried commenting out the XferCommand and using wget but that fails even worse.
Thank you for posting this, I am glad I am not the only one experienceing this. I was about to give up searching and post too.

Broadband speed suddenly dropped

For the last 7 months we have had good BB speeds of around 6Mbps this has suddenly dropped down to under 0.5Mbps.
I have reset the Home Hub 2 & had it plugged directly into the test socket on the master unit which has not changed anything.
I ran the BT Speedtest which gave the following:
Download speedachieved during the test was - 414 Kbps
For your connection, the acceptable range of speeds is 50-500 Kbps.
Additional Information:
Your DSL Connection Rate :5824 Kbps(DOWN-STREAM), 448 Kbps(UP-STREAM)
IP Profile for your line is - 500 Kbps
I did notice the blue "b" led flashing yellow a lot last eve, far as I know this means the Hub is updating itself
Any ideas?
Thanks
Dave
Solved!
Go to Solution.

Hi Welcome to the forums
If you post the full stats from your router
For homehub – type 192.168.1.254 into your browser
Navigate to ADSL Settings or use the A-Z at the top right of the home page and scroll down to ADSL Settings and click on it
Click on More Details and then post the full results.
Have you tried the quiet line test? - dial 17070 option 2 - should hear nothing - best done with a corded phone. if cordless phone you may hear a 'dull hum' which is normal
your ip profile is low this is due to disconnections and providing you can maintain a stable connection with no hub restarts for the next 3/5 days your profile should increase automatically this will then improve your download speed
Then someone here may be able to help and offer more advice.
This is a customer to customer self help forum the only BT presence here are the forum moderators
If you want to say thanks for a helpful answer,please click on the Ratings star on the left-hand side If the reply answers your question then please mark as ’Mark as Accepted Solution’

Sudden drop of speed - internet vitually unusable ...

Hi all
I had a look round the service status page and saw nothing for my area, so wondering if it's just me, but last night as I was playing my usual evening online poker, I basically lost all connection.
Now, I'm on Total Broadband Unlimited, have a Home Hub v2, and have done since February. Am in the WD17 area, and nothing has changed from when it's been working fine all these months.
So, as I was merrily playing along, the 54.0 Mbps connection suddenly drops out to..... 1.0 Mbps. And stays there. Do a Hub reset - no improvement.
So come back from work today to see if there's any improvement - and marginally. It's now randomly fluctuating between 2, 11, 15, 18 & 54. Still pretty much unusable.
Any ideas?

Those figures look like wifi data rates not adsl
enter
192.168.1.254 in browser click A to Z top right
then ADSL enter pas and click MORE DETAIL
POST RESULTS
Also post results of test at http://speedtester.bt.com/
if you are on wifi connection to router then
Download Inssider2 for free from http://www.metageek.net/products/inssider/download
or
Xirrus wifi inspector again free http://www.xirrus.com/library/wifi_download_redirect.php
they l show you any wifi around you that could cause problems
and the channel they use just pick a free one
If any post helps tick the star box on the left
Just cause Im paranoid dont mean they are not out to get me

Suddenly slow song transfer to iPod

This appeared fairly suddenly, without any other symptoms; no hard disk noises or freezes or icons on the iPod screen, which are often signs of failing HD.
But now my iPod mini Blue (4G, first gen.) is very slow transferring songs from iTunes 6.0.4 to the iPod, using drag-and-drop from Library window in iTunes. Seems like USB 1.1 speeds - i.e. about same speed as transferring songs onto my Rokr cell phone: e.g., about 1 minute per 4MB song.
I also checked data transfers, using iPod as FW or USB2 hard disk, and the transfer speeds are about the same - so it's not just an iTunes thing.
Slow speeds using either FW or USB2 cables; have also tried different cables, so it's not that.
The iPod works fine: playback is good, no skipping; above all, no grinding or other problematic HD sounds. Battery lasts about 4-5 hours in normal use.
Any idea what it can be?
Tried solutions: I reformatted the HD with Disk Utility. Reformatted as Mac OS Extended (Journaled), with no OS 9 drivers.
I then used the latest iPod updater to update the iPod.
I also tried to use DiskWarrior 3.0.3 to optimize the HD: when I graphed the iPod HD, DW showed about 50% out of order and needing optimization. But even after optimizing and replacing directory, there was no change in transfer speed.
Any help or advice appreciated.

Are you USB ports only 1.1 or do you have USB2 (high speed) USB ports?
If you like math, here is a previous post of mine on the subject of USB 1.1 transfer speeds with the iPod...
http://discussions.apple.com/thread.jspa?messageID=2769205&#2769205
USB1.1 is a top speed of 12 Mbps while USB2 is up to 480 Mbps, so if you have USB2 ports, just do the same math with that number.
Patrick

Problems with Photoshop performance and data transfer speed on iMac

Two months ago, I started noticing slow performances using Photoshop (above all using clone stamp tool) on my 27" iMac (late 2012). I did the AHT and I found that 8GB of 32GB RAM were broken.
I removed them but the problem didn't disappered, I also noticed that data transfer speed (both copy and paste from/to internal HD and from CF card/external HD) was really slow.
I tried many solutions suggested by Apple support, none of them worked out. At the end, I tried uninstalling and re-installing Photoshop: no more problems!!!
10 days ago, I received a new 8GB RAM module and so I installed it back... suddenly, the problem came back, I tried re-installing again Photoshop but the problem, this time, still persist!
Does anyone had the same experience? All other CC programs work well (LR, AE, Premiere...)

yes, it does!
what seems to be very strange to me is how data trasnfer speed could be affected!
(just to say, I've already tried reset of SMC and PRAM, I've tried with different accounts and I've also re-installed the OS, next step would be formatting the disk and installing the OS from zero)

Very slow network directory listing - but fast data transfer speed once listed?

Hello,
I have really tried to sort this myself before opening up to the community, however I have run out of ideas, and hope someone can offer the magic solution I have missed.
I am currently using the 3.4ghz i7 iMac on a 1GB LAN, running OSX10.7.2 - connecting to a Windows Server 2008 (Running Release 2) over ethernet.
If i go to a network directory that i haven't recently accessed it can take up to 60 seconds to show the contents of that directory. Once i have accessed that folder, if i come out of it and go back in it will be instant again - but the first time it lists the directory it looks like i have opened an empty folder - which after anything from 10seconds to 1 minute will suddenly show the files that are there.
Internet connectivity is fast through the network, and file transfers across the LAN are fast. (showing as approx 300mb per second) I can play and edit HD content across the network with no slowdown so I am confident that this issue is not related to the network speed itself, and is more to do with a setting on this mac.
Symptoms are very similar to this post: https://discussions.apple.com/message/12245148?messageID=12245148&amp%3b#1224514 8 - however i understand that in OSX Lion - SMB was removed - so i cannot find this file to edit.
I have tried bypassing additional hubs in the network by wiring direct cables to the switch that is connected to the file server, this made no difference.
I have also tried disconnecting the ethernet cable, and running over wifi. This fixes the listing problem, but when editing HD content over a network drive, this connection is not fast enough to carry the data without interruption (some projects are linked to up to 900gb of hd video content!)
Using ethernet, I have tried DHCP, DHCP with manual address, and manual mode. All reproduce this problem. i have tried using the windows workgroup, and tried without it.
I have also followed this suggestion: https://discussions.apple.com/thread/2134936?threadID=2134936&tstart=45 and used OpenDNS. this did not fix the issue.
For argument sake, I have also just tested a Macbook Pro running Snow Leopard to see if it was OS related. This reproduces the exact same problem, near instant directory listing on the wifi, a long and arduous wait on ethernet.
I cannot work out why directory listing is instant over wifi, but not over ethernet on 2 different macs, running 2 different versions of OSX. I also do not understand why if the network is having trouble listing the directories - the data transfer speed is 300mbps when i copy files across the wired network from the file server to the mac.
Does anyone have any other ideas as to what could be the problem here? We are about to start work on a very large project, where the content we are editing is spread out across around 200 different network folders (different shoots captured over the past 2 years). We really don't have the time to wait 60 seconds each time we need to access one of those directories to look for a file, and I am very close to pulling all my hair out!
I really look forward to hearing from anyone who can offer any insight.

If you are suspecting that the Windows update had something to do with your LAN going slow, then try the following:
1. Look for updates for your clients LAN NIC driver; or
2. Un-install the updates.

External firewire hard drive reverts to slower transfer speeds

This is the strangest hardware problem I've come across. I'm running a unibody mbp (June 2009) with an external WD 2.0TB Caviar Green drive mounted in a firewire 800 enclosure made by icydock.
Lately, I've noticed that after an unknown amount of uptime, the speed of file transfers to the WD external drive slows down dramatically. I figured this out by watching my time machine transfers take a bit longer after awhile, and I verified this using aja system test and speedutilities.
When I boot my mbp in the morning, file transfers and time machine backups to the external WD transfer at a rate of about 67-75MB/s. This is the speed the drive should always be working at since it's connected via firewire 800. Aja speedtest verifies the speed is as it should be as well.
Then, after a couple hours of using my mbp, or even later in the day, I'll transfer a file to the external WD or run a time machine backup and find that the transfer will only run at a max of 29-35MB/s. This is exactly half the speed the transfer should be going at. Subsequent transfers stay at this slower rate no matter what I do.
However, I've been able to fix this problem by unmounting and remounting the external WD or restarting my mbp. After doing either of these actions, the WD external goes back to contant transfers at 75-80Mbs. So something is happening where the longer the mbp is running, or after some sort of disk activity, the external WD reverts to a slower transfer speed (closer to FW400). I can't isolate whether it's an issue on the mac os side or the hard drive or the hard drive enclosure because I can make the hard drive go back to optimal speed again merely by unmounting and remounting it. This works consistently until a few hours later when the drive begins to handle transfers at half speed again.
I run hourly time machine backups to the drive. The time machine backups can't be the culprit because the drive remains running at optimal speed after the backups (verified with aja system test and speed utilities)
Any possible ideas as to why the drive cuts down to half its optimal transfer rate after a bit of time? I can't figure out the cause of this, and the consistency of the drop leads me to think this is an issue with the power management on the drive since it reverts to full fw800 speed when I umount and remount the drive or restart my computer. Could this be an OSX issue where for some reason the system isn't negotiating the fastest speed?
Any help appreciated.

From the SoftRAID manual:
Fire hubs and disk drives. FireWire hubs are notorious for introducing errors and instability onto the bus.
Make sure that all of your consumer electronic devices (iSight, cameras, scanners) are connected to a separate FW bus. These devices are not built to the same standards as storage devices and known for introducing errors onto a FW bus.
Cables. While most cables work fine with a single device, many cables will introduce errors when 2 or more disks are connected to the bus.
http://www.softraid.com
http://www.softraid.com/demo.html - manual and demo
Output can be to any drive or partition. When you lauch iMovie it asks where to store your project.
I just bought a camera, and curious myself to see if I can take 10 minute clips and use iMovie/iDVD so that it will auto-play. I may end up buying Pogue's "iMovie Missing Manual" or something.
iMovie Discussions

Sudden drop in transfer speed

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