Mixing RAM Speeds

Hi there,
I posted this in the "Using Mac" forum, but unsure how to delete it, so I reposted here! I'd like to upgrade my memory. Currently, I have the factory installed 1GB RAM. Can I mix memory speeds? For example, will I be able to put 2GB in the empty slot and still have improved performance? I went on crucial.com, which recommended this, but I wasn't sure if this would be okay.
Thanks,
Rhys

I did not know that about that group of Mac's running G4, I guess I did learned something new today
What I would like to add to all of this is also that it does matter when you deal with dual channel memory like on the Mac Pro's in that case you will have to mach the same size and speed other wise it will not read correctly.
I have had misc memory size on my MacBook Pro 15" and my iMac as well (Intels) and it was working just fine, so you wont have any issues. Although Apple does recommends you to matching pair.
I hope this answers your questions,
Goran
G.

Similar Messages

Mixing RAM Speeds...No Ben Hur jokes please ;)

Is it ok to mix RAM speeds. Somehow I purchased some RAM awhile back that was PC2-3200U-255 for my Quad. Oops, I never noticed that is wasn't what came with the computer, the 4200-444. Well, I just bought some more RAM at 4200-444, and noticed that I had varying speeds. Will this variation pose any problems?
Thanks!!

Thanks for the link Josef. Very informative. Unfortunately, I am still confused (my permanent state).
So I checked my invoice from my purchase and it looks like I purchased 5300 instead of the 3200 that is showing in "System Profiler". I opened up the computer and indeed it is 5300. So, is mixing the 4200 and 5300 a no no? Is the 5300 in fact being read as 3200? And doesn't the other RAM automatically run at the lowest speed, no matter what speed is highest?
Thanks, sorry that I don't get it. I did searches and am still confused.
Slow learner,
fatlanglois

Mixing RAM Speeds In iMac G4 1GHz 17" Flat-Panel?

I'm just checking here.
I have an iMac G4 1GHz 17" Flat-Panel, Model M8935LL/A (USB 1.1 version) that currently has the standard 256MB PC2100 (266 MHz) RAM module installed in the factory slot, and a 512MB PC2700 (333 MHz) RAM module installed in the bottom (user-accessible) slot. I bought the machine direct from Apple, so despite the "official" spec (which calls for PC2100 RAM in both slots), it's obvious that Apple knows PC2700 RAM will work in that machine. My understanding is that the faster PC2700 RAM simply downclocks to accommodate the lower 266 MHz bus speed of the M8935LL/A. As I understand the DDR SDRAM spec, any DDR SDRAM (PC1600 through PC3200) module will simply overclock or underclock to accommodate the host bus speed...but feel free to correct me if I'm mistaken on that point.
I'm fixing to upgrade the hard drive to a larger capacity model. I've done it before, so I know it's no picnic. Since I have to go past the factory RAM slot anyway to change the hard drive, I figure I might as well upgrade the internal RAM to the full 1GB limit. (Yes...I know Apple says you can't exceed 512MB in either slot, so please—no remonstrances about sticking to Apple's spec. The spec is wrong.)
Obviously, it's possible to mix the two RAM speeds between the two slots, since Apple shipped the computer that way. Here are my questions:
• Is there any downside to going the other way when I upgrade the RAM—that is, putting a 1GB PC2700 (184-pin) module in the factory slot, and a 1GB PC2100 (200-pin) module in the user slot? The reason I ask is because my preferred supplier (OWC) can't supply me with both modules in the same speed.
• Is there any performance advantage in both modules being the same speed—that is, both PC2100 or both PC2700? If not, I'll just buy the one of each speed that OWC has available.
Thanks!

jjw wrote:
So, you know have 2Gb available in your flat screen imac?
Yes indeed—2GB confirmed as available by Apple System Profiler. Both modules are PC2700. Everything is working fine.
I guess I can understand why Apple discourages users from replacing the 184-pin "factory slot" module. There's not a whole lot of slack in the motherboard connector cables, so it's best to disconnect them in order to get the bottom section to lie flat on the workbench. I suppose some folks might be hesitant about disconnecting things, but it's really quite simple, and involves only three connectors. After having changed the hard drive a few years ago, replacing the RAM was a piece of cake by comparison.
A word of caution to anyone who's going to attempt it, though. There are TWO heat sink interfaces between the bottom section (where the motherboard is mounted) and the top dome. Those heat sink surfaces are coated with thermal paste at the factory, but the compound dries out over time, becoming a rubbery membrane between the heat sink surfaces. Once you separate the top and bottom sections, the membrane rips apart, and the firm connection between the heat sink surfaces is permanently gone. It's a bad idea to simply put them back together after you change the RAM module; you won't get a good thermal connection.
The solution is to scrape all of the old rubbery compound off all four surfaces (two on the bottom and two on the top section). I did it with a piece of PVC, but you can use anything with a sharp edge that won't scratch the metal surface—even your fingernails will work, unless the old compound has dried out to the point where it's hard. After you scrape the old gunk off, apply new thermal paste to all four surfaces.
The other maintenance item you can perform while you're in there is cleaning out all the dust, which accumulates in vast quantities and interferes with cooling. I vacuumed it out with a plastic crevice tool, being careful NOT to touch any of the components with the tool. Vacuuming can build up a static charge on the tool, especially in dry environments, and high static voltages aren't friendly to microprocessors. I used a securely grounded anti-static wrist strap throughout the entire operation, and even wrapped it around the vacuum tool.
Good luck!

Mixing RAM speeds in Mac Pro 3.1

I recently bought a used Mac Pro 3.1 early 2008 2xquad core 2.8 gHz. It came with 6 1 Gig 667 MHz in RAM. This Mac takes 800 MHz- can I fill one of the risers with 4x4 Gig 800 MHz while temporarily keeping 4 1 Gig in the other riser? I realize all will (should?) be running at 667 until I switch to all 800 MHz; but can they be mixed as long as they're on their own riser card? I can't afford to replace all the RAM at once, and am hoping to upgrade in waves. An extra 4 Gigs isn't much but it would really help for a short time.

I thought I/we already went through this a day or two ago, not you? then someone else.
Check it out.
Same over on MacRumors and links to ebay and Amazon
Mac Pro 3,1 memory question
And yes you can mix and match - as long as each paired set and if even one set is 667 then the memory controller will downlclock for all.
http://www.barefeats.com/harper5.html

Mixing RAM--Speed differences

Hi,
I ordered 4x1 GB DDR2 PC2-4200 non-ECC memory from an online vendor.
I recieved instead 4x1 GB DD2 PC2-3200 non-ECC memory.
I installed it and the system sees the memory but now I have a mixed bag...
DIMMO/J6700 256 MB DDR2 SDRAM PC2-4200U-444 (existing)
DIMM1/J6800 256 MB DDR2 SDRAM PC2-4200U-444 (existing)
DIMM2/J6900 1 GB DDR2 SDRAM PC2-4200U-444 (existing)
DIMM3/J7000 1 GB DDR2 SDRAM PC2-4200U-444 (existing)
DIMM4/J7100 1 GB DDR2 SDRAM PC2-3200U-288 (added)
DIMM5/J7200 1 GB DDR2 SDRAM PC2-3200U-288 (added)
DIMM6/J7300 1 GB DDR2 SDRAM PC2-3200U-288 (added)
DIMM7/J7400 1 GB DDR2 SDRAM PC2-3200U-288 (added)
Mac seems to be running ok, but what grief am I asking for running this memory configuration? Am I limiting the Mac's performance?
Help please,
cman65
Dual 2.3 GHz PowerPC G5 Mac OS X (10.4.8) 6.5 GB DD2 SDRAM

Having same type of problem. Purchased (2) PC2-4200U modules from Computer Memory Outlet for my Late 2005 Dual G5. Installed them and the System Profiler says they are PC2-3200U-288. Returned them and they sent me two replacement modules by EDGE Tech Corp, same thing.
EDGE Tech Corp Support assured me they were the correct modules for my G5. I swapped the modules with my existing (correctly listed) memory in different slot pairs. They still show up as PC2-3200U-288. All other Apple installed memory is correct.
Don't know what's going on here.

Mixing ram sizes

Hello,
I recently purchased a macbook pro i7 late 2011 edition. It currently has 4GB of ram(2x2GB). I am wondering if it is possible to purchase a single 8GB(1x8GB) stick of ram and trade out one of the old 2GB sticks in order to have a total of 10GB of ram. I am aware 16GB ram kits are available but they are currently too expensive for me so atleast this way I could purchase one stick of 8GB for now and then purchase another down the road.
8GB of ram is not enough for me. So my question is if whether or not I can mix ram sticks. Please only respond if you know for a fact and why, I don't appreciate people making guesses.
Thank you!

No one can answer your question with certainty. Some people mix different RAM brands and sizes and even speeds, and don't have any trouble. Others try it and have nothing BUT trouble. No two Macs or Mac users are alike in all respects, so there's no knowing why it works for one and not for another. It's a safer bet to use exactly matched pairs, but you might be fine with whatever mismatched modules you choose. If you buy from a vendor who offers a lifetime warranty, you'll probably be able to return anything that doesn't work out for you. But you can't eliminate the chance of getting bad RAM no matter what you buy, and you can't be sure that even a good module will behave perfectly when paired with a module that you have now.
There are some vendors who offer RAM modules in pairs from one manufacturer but in unmatched sizes, and warrant them to work properly together. You may want to consider buying a 4GB and an 8GB module from such a vendor, adding a small amount in cost but giving you 12GB and a solid warranty. Here's one dependable source:
http://eshop.macsales.com/shop/memory/Apple_MacBook_MacBook_Pro/Upgrade/DDR3_133 3MHz_SDRAM
Note that the extra 4GB only costs $15 more than a single 8GB module.

Mixing ram whats best

hi im currently running 3 1gb sticks of ram but one of the sticks is older than the others and only runs at 533mhz the others usally run at 800mhz but because of the older stick all sticks run at 533mhz.
my question is.
is it better to run 3gb of ram at 533mhz or 2gb at 800mhz?
here are the sticks im mixing
http://www.ebuyer.com/product/98710 andhttp://www.ec.kingston.com/ecom/configurator_new/PartsInfo.asp?root=us&LinkBack=&ktcpartno=kvr533d2n4/1g
im running a p7n 750i sli platinum
cheers

Quote from: jimmi1 on 06-June-08, 18:27:11
hi im currently running 3 1gb sticks of ram but one of the sticks is older than the others and only runs at 533mhz the others usally run at 800mhz but because of the older stick all sticks run at 533mhz.
my question is.
is it better to run 3gb of ram at 533mhz or 2gb at 800mhz?
here are the sticks im mixing
http://www.ebuyer.com/product/98710 andhttp://www.ec.kingston.com/ecom/configurator_new/PartsInfo.asp?root=us&LinkBack=&ktcpartno=kvr533d2n4/1g
im running a p7n 750i sli platinum
cheers
I agree with everyone on mixing ram isn't the best idea in the world, but it's certainly not the worst either. Myself, I have mixed memory on several occasions with no problems at all. While you may lose a very small amount of spped from going from 800 down to 533, it is immesuarable without a benchmark to tell you. Also, losing dual channel is a very small decrease as well. I've tested it on many of my systems and the biggest loss was only 5%.
If you need all 3GB of RAM then I suggest, after you have thoroughly tested your new ram and make sure they are 100% stable, is that pop in your extra ram and run some stability programs such as memtest86+ for overnight or longer (8hrs minimum). If you get no errors then you should be good to go.
also, to compare speed loss I'd run some benchmarks before adding the extra memory such as 3dmark/pcmark and compare them afterwards and see if it is worth the loss to you. I'm sure you won't even notice it at all without running the benchmarks telling you they are running slow.
Good luck
-=Mark=-
ps. also if you start having issues down the road then remember to remove the old RAM and retest just to be sure they aren't the culprit.

Mixing Ram with different CAS latencies in K7n2 Delta-L?

I have been using 512mb Kingston Value Ram in my computer, pc3200, with CAS latency of 3.0. I just purchased some Corsair value select 512mb ram pc3200 with CAS latency of 2.5. I know you are not supposed to mix ram with different speeds (like 400 vs. 333) but does it matter if the CAS latencies are different?
I'm running an AMD XP 1800+, K7n2 delta-L, nforce2 motherboard from MSI. Someone at a computer shop told me they tried mixing Kingston 3.0 CAS with Corsair 2.5 CAS, and said his computer wouldn't even post. So I'm wondering if this is an isolated problem, or you will always run into this problem if you mix ram with different CAS latencies.
If anyone has experience with this issue, please share with the board. Thanks!
Chris

The age old question, will the components I bought be compatible ? There are those that have bought identical matching memory that didn't work. In my case, I had an ECS K7S5A that used PC2100 Crucial memory, the sticks neither matched (at one time they did, but one stick died and they sent me the closest thing they had.). Neither of these Crucial sticks was identified by a configurator as being compatible with the K7N2 Delta L that I decided to buy. In the end, not only did both sticks work, but I put them in as single channel mode (ram slots 1 & 2), but later changed the configuration to dual channel mode (ram slots 1 & 3, even 2 & 3). It worked flawlessly in all three configurations. Sorry for the long answer, but in essence, there are no guarantees and your worries will drive you crazy. When memory is mixed, you reduce the likelihood of compatibility, even when you go beyond the recommended products that were specifically identified.
That guy at the computer shop, did he ever indicate or isolate the true reason why the memory wouldn't work ? Maybe, maybe not. I would think with a disparity in memory, the bios is the key to setting the settings for the worst stick of the bunch. Then again, the products you get might overclock to what the better sticks run at. My assumption is that mixed sticks, the bios retards settings to this in "auto" mode. When you force it manually, it may work or it may fail. One thing you oughta know, each and every stick has the manufacturers id encoded onto them at the very least, just like the firmware on other items indicates a manufacturer code and other data that allows these things to be compatible. So know you face that battle going in with any of them. If the bios programming doesn't allow it to work, from that perspective, there'll be problems.

Mixing ram brand ok?

http://shop1.outpost.com/product/4292564
Id like to get some of that ram but right now I have Corsair Value Select 512. The board seemed real picky as to where I put the ram and it only liked it in the 3rd slot so I figure maybe its real picky about the ram in general. I dont overclock but is mixing ram like that ok? Or should I just get another stick or value select.

Yes it does work i've just done it over the weekend. Mty son's just upgraded his PC so I pinched his old memory 2x256mb 3500 Geil.Golden Dragon 433.
Put my ballistix in slot 1 & the 2 single sided eil in 2 & 3.
at stock ballistix run 2,2,2,6 geil 2,3,3,6 so tried it at stock 1st at the lowest speed module 2,3,3,6. I upped the memory voltage a notch & jobs done. Can't get back yet to the 225 I had (dropping Cas to 2.5) but have got to 220.
Think In your case it depends what you value most 1GB or 512MB good performance memory MUSHKIN 512 MB 3200C2. Forgive the pun but its a bit like harnessing a racehorse & carthorse together. You will have to manually set your timings to slowest module Value & so won't see the benefit of the MUSHKIN. Alternatively put in the MUSHKIN & enjoy the faster timigs you can now get.
luck

DC Mixing RAMs on E7205. Will it work?

I have 2X512mb DDR266 kingston value ram. 2.5-3-3-7.
Could I use Kingston 1.0GB ( 512 x 2 ) PC3200 DDR-400 TWINS Hyper X/ CL I don't know.
Will Dual channel work with the 2 pairs of different RAM speed? Or the PC would not boot at all?

It's always not recommended to mix the RAMs though you may want to try.

Mixing RAM Modules (1gig + 2gig = 3gig)

Hello,
I am about to buy a Mac Mini and I am on a tight budget. The one thing I want to do for sure is upgrade the memory, but I'm in a quandary of sorts given my budget. The retailer where I want to buy the Mini from only sells the appropriate RAM for the Mini in 2gig modules. So here's my question: I know it is possible to mix the stock 1gig stick with a 2gig stick to get 3 gig of RAM total, but will it be worth it to me? I realize that the best configuration would be to slap in 2 2gig modules in and just be done with it, but with 3gig, would I be appreciatively shooting myself in the foot and killing the machine's performance, or wouldn't I notice? I need to have the memory installed at purchase because I am physically handicapped and adding the memory myself is out of the question. And after researching how to replace memory on the Mini, I wouldn't have the courage to ask anybody I know to attempt to do it after buying it. Is mixing RAM modules a good idea?
Thanks in advance.
Malcolm

Nope, I am not confused, There does have generation between Mac mini model. Maybe not official, but we all know. Check About This Mac ---> More Info ---> Model Identifier : Macmini2,1 (That means, 2nd generation)
Macmini 3,x (means 3rd generation I supposed)
And the 3rd generation doesn't support Dual Channel, referred to Crucial.com
http://www.crucial.com/store/listparts.aspx?model=Mac%20mini%20%28Intel%20Core%2 02%20Duo%202.0GHz%20DDR3%29%20MB463LL/A&pl=Apple&cat=RAM

Mixing Memory Speeds

Apologies, wrong thread, please ignore.
Message was edited by: Rhys Bethell

Hi Rhys,
i think what you are talking about is mixing memory size, not speed. You can not mix memory speeds, especially in Macs.
You can mix memory size in most Macs. Very few Macs use memory interleaving that requires exactly the same size memory modules to work best. The iMacs allow mixing size with no impact on performance.
Go ahead, Crucial is very good with Macs and can be trusted.
Also very good is Other World Computing (OWC).
Ralph

Mixing ram

recently got my new imac, and since i use it mostly with logic, and i respect most opinions here, i'll ask this here.
i am thinking about buying a 512 for my imac from someone on craigslist . he pulled it from a MACBOOK. i know both are sodimm and both are pc-5300 - his is hynix, i don't know what mine is. for $75 i could bump my ram by 100% which sounds great, but i've heard some people have reservations about mixing ram. thoughts?
ps. i know matched ram gives a slight performance boost, but i just need more breathing room, and $75 seems like the right price.

yeah kid i'm with jord on this
i just had a big thing with RAMS not long ago leading me to deleting everything on my harddrive and also not being able to install DVD and app been crashing alot
but after I removed them rams things runs smooth
so RAMS plays a big roll in your system, so get the best and make sure they match and work as well
stash

Mixing RAM Manufacturers?

My apologies if this has been asked before; I searched the forum but couldn't find anything that answered my question properly. So-called 3rd party Memory is new territory for me.
I'm looking to upgrade the RAM in my iMac at home; it's a late 2006 20" 2.16 C2D.
I was wondering if anybody could tell me if mixing RAM by different manufactures will cause any adverse effects or instability? Of course taking into account that the memory is in perfect working order. Also, what manufacturers available in the U.K are most reputable with regards to stability and useful working life? I work in music production so good RAM and stability is a must.
Currently I am considering a single Crucial 2GB module, mainly because they seem to have a good reputation around the forum and it's very reasonable priced.
http://www.crucial.com/uk/store/mpartspecs.aspx?mtbpoid=5A5FD16EA5CA7304
I'm also considering buying a further 1GB module (possibly Kingston) soon after should 2.5GB in the computer not be enough.
Lastly; would there be any benefit to buying a second 2GB module (instead of the 1GB)? I know each slot can accept a 2GB stick, but I keep getting conflicting info as to whether 4GB can actually be addressed in the late 2006 white 20" iMac (despite the spec being 3 gigs).
Cheers.

£32 for one 2GB module! Now I feel seen-off. At the end of November I decided to buy just a 1GB SODIMM as that was £17 versus the £57 they wanted for a 2GB modules. Today I could have bought a full 4GB for £64. Nevermind, I don't actually need that much RAM.
At those prices I'd buy 2GB now and then 2GB later. You'll get to use 3.3GB as den.thed says and because you'll have two modules from the same OEM you'll be sure they will pair up and you'll get the benefit of matched RAM.
I'm also going to re-iterate my usual gripe about Kingston: Kingston Value RAM (slightly more than Crucial) doesn't work in Macs (Kingston themselves told me that). It caused Kernel Panics in my old iMac. If you use Kingston System Specific RAM (about twice the cost of Crucial) it'll work just as well as the Crucial.
mrtotes

Mixing ram pc2100 &pc3200

My system currently has one stick of PC2100 RAM, 512MB.
I would like to bring my system memory up to a gig of RAM, but I don't want to buy another stick of PC2100, cause it won't help me for future upgrades. but i of course don't want to just get rid of the PC2100 stick i already have.
would there be any harm in mixing the PC2100 with PC3200? I know the PC3200 would just run at 133/266, just wondering if any problems/instability might occur my mixing the two.
I'll WILL match brands however, and make sure they are both Kingston Technology, cause i've heard that this kind of mismatch can definitely cause problems.

Mixing RAM such as you are proposing, is always a crapshoot. It may work ok, but I would think very hard before trying it. You might be able to make it work by setting the timings manually, but even that does not always work.
I would hate to see you buy PC3200, and then not be able to use it with the existing RAM.
You may be better off buying enough PC3200 to replace the existing RAM, while upping the total amount of ram, and avoiding the trouble all together.
While some have claimed to have no problems mixing RAM, most have had bad luck with trying it.

Mixing RAM Speeds

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