Mixing RAM modules on a 800Mhz machine

I have a new Mac Pro. 800Mhz. I want to install more memory but n find any 800Mhz 2Gb modules for sale as yet.
I have the option of installing 667mhz modules.
Will this cause a problem mixing 800Mhz and 667Mhz modules?

You posted your question in the wrong forum. This forum is for pre-G3 Macs. You should repost in the Power Mac G5 forums @ http://discussions.apple.com/category.jspa?categoryID=108
That said, this will probably answr your question.
You can't use a processor speed lower (667Mhz) than that specified (800Mhz). Plus there are other restrictions. See *How do you upgrade the RAM in the Mac Pro? How much RAM of what type does it support?*
@ http://www.everymac.com/systems/apple/mac_pro/faq/mac-pro-how-to-upgrade-memory- what-type-ram.html
You can buy the 800Mhz RAM at Other World Computing @ http://eshop.macsales.com/Search/Search.cfm?Ne=5000&Ntt=MacPro+800MHz+MatchedPair&Ntk=Primary&Ns=P_Popularity%7C1&N=7318
 Cheers, Tom

Similar Messages

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 RAM Modules

Several weeks ago, I replaced my 256 MB RAMs with 2 1 GB modules in a late 2005 G5. They seemed to work fine, though my GPU seemed to be running a bit hotter. I just installed an additional 2 GB bought from OWC, and also added back the 2 original 256 MBs to bring my total to 4.5.
Looking in System Profiler, I see that my original 256s and the latest 1 GB modules are PC2-4200U-444, as specified in the online compatibility guide. I see the I GB modules from my first upgrade are PC2-3200U-288.
I bought them at a local shop- for way too much money, by the way - and was told that the number printed on them was wrong and they were compatible with my model. Is that right, or this a problem?
Thanks

Hi! The PC2-4200 modules are the correct ones and you shouldn't run anything slower. You can run faster ones but you shouldn't run slower ones or mix speeds. And if the computer sees them as the slower ones then most likely they are! Tom
Message was edited by: Thomas Bryant

HT3918 Mixing RAM modules in a late 2009 iMac

I have a late 2009 27" iMac that came with only 2 Gig of RAM. I recently ordered 16 Gig of RAM (4 modules), but they only shipped me 8 Gig (2 modules). I installed the 8 Gig (still leaving me with 2 empty slots), can I also reinstall the two 1 Gig modules that I removed for a total of 10 Gig?
Also, if I order an additional 8 Gig from another company will it cause problems to mix products from different companies?

Welcome to the Apple Support Communities
The Late 2009 iMac came with 4 GB on all the models, so maybe you have an Early 2009 iMac.
Apart from that, if you have a Late 2009, you can use 16 GB of memory, so you can install two 4 GB modules and two 1 GB modules, for a total amount of 10 GB, without any problem. If you have an Early 2009 iMac, 8 GB of memory are the maximum.
To buy memory, I only recommend you OWC and Crucial, that provides compatible memory with Macs. Other brands may work, but with OWC and Crucial you can be sure that memory will work with your computer > http://www.macsales.com

Mixing memory module of different sizes in G5-8 slot machine

is there a problem with Mixing memory module of different sizes in G5-8 slot machine
I have 2gb on four slots with 512 memory chips
Can I upgrade my memory with 1gb chips in the remaining four slots.

Hi epospiech-
Yes you can.
Instructions here: Memory (DIMMs) Replacement Instructions
Luck-
-DaddyPaycheck

Z77A-GD65 no longer boots with 4 RAM modules

I had 4 x 8GB Cosair Vengeance LP that used to work fine, but no longer boots into Windows with 4 but only with 2 RAM modules. Any help in solving the issue would be appreciated. ( I need 32 GB as I run many virtual machines )
The 4 modules worked fine for few months until couple weeks ago, when I saw issues with booting into Windows 7. The workaround was to "warm up" by leaving the PC in BIOS for about 5 minutes and it would boot fine. Since couple days ago, it would POST but not boot into Windows or into live Linux on USB, so I started troubleshooting with bare bones first ( MB, CPU, 1 RAM, PS ) and then starting adding more and more components until I found that 1 and 2 RAM modules worked in either black or blue rail but with 4 RAM modules, it will POST, but not boot at all into either USB based live system or into Windows 7.
Memtest with 2 separate sets of modules pass with flying colors. Mixing the sets work fine too, but add 2nd set (i.e. 4 modules) and it fails to boot. I am leaning more toward believing the issue is with the MB than with the RAM since mixing them doesn't throw any memory error.
Any suggestion on how to check if it's the RAM or MB ?

Quote from: PirateDog on 25-November-13, 00:23:30
If these were 2 kits mixed, ...
These were 2 mixed kits.
Quote from: XFM on 25-November-13, 07:01:42
What voltage is the RAM running? A slight bump up in voltage might help.
As to voltage, I started with standard 1.5 and then incrementally upped it to 1.65v. At 1.6v and above, it does boot into Windows, but intermittently goes into BSOD... Works perfect with 1.5v with 2 RAM modules.
I'll save the money for next build instead of going for 32GB kit. ... guess I'll live with 16GB for now.
Thank you all for the advice.

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 memory modules of different sizes in a Mac Mini

I have a MM Intel Core Duo with a 1.66GHz processor and 512 MB 667 MHz SDRAM. Model Macmini1,1, 32 Bits, SMC Version (system): 1.3f4.
Anybody know if you can mix memory modules in it? I have the standard 256 modules (2) and would take one out and replace it with a 1 GB one. Can this be done?
Thanks

+Anybody know if you can mix memory modules in it? I have the standard 256 modules (2) and would take one out and replace it with a 1 GB one. Can this be done?+
Yes, you can do this. You will get a slight performance hit on video, but that will be more than offset 99% of the time by the extra RAM reducing overloading of the Virtual Memory system.
However, it is enough work to replace the RAM and RAM is cheap enough, that I'd recommend putting in two matched 1 Gig modules instead.

Mixing RAM Mac Pro

Hello!
I have read the other posts about this issue but I want to make sure I understand it correctly.
Do not mix 4 & 8gb RAM with 16gb and higher RAM. That part I get, but what I want to be sure of is that I can configure the RAM as follows...
2 slots with original 4gb RAM and 2 slots with 8gb RAM
According to what I've read, this should be acceptable, correct? How much will this configuration compromise the performance as I can't afford 4-8gb ram modules? I work with a lot of large image files and usually have Lightroom & Photoshop running at the same time. Even with the 16gb I currently have, I get the force quit window popping up to tell me apps have been paused quite a bit.
Thanks for help!! Have a good one!!
Lisa Rose

Yes, that's acceptable. It won't compromise performance to put in more RAM.

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... DDR3L and DDR3.

Hey,
I have two MSI.. One is GT70 and one is GT72 (dominator pro).
The GT70 has 24gb DDR3 ram, and my new GT72 only have 8gb DDR3L ram.
My question is. Can I take some DDR3 ram and put into the GT72 that runs DDR3L ram? Can I mix them both at the same time that is?
Can I put 8 DDR3L + 16 DDR3 ram in the GT72, or will this malfunction somehow? It would suck to have to just throw away 16GB ram that I bought to my GT70 about 3 weeks ago.... Damn it....

i think thats what Zipper meant if you put a 1.5V module in your GT72 that as got DDR3L module in it by default, it will make the 1.5V moddule fry out since it isnt compatible.
DDR3L = 1.35V
DDR3 = 1.5V
So putting 1.5V module in your GT72 that has 1.35V ram module in it will kill the V1.5 since GTX 72 runs with DDR3L not DDR3.
Update: Nvm Zipper meant other way around but i think it would happen same if you put other way around that 1.5 module will die since not enough voltage.

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 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

PowerMac G4 having problems with new RAM modules!

dear all,
I’ve recently got 2 512 MB Ram module from a British eBay dealer, to be used on 2 different but very similar PowerMac G4 AGP Graphichs 400 MHz machines.
I installed the first module in my father’s Mac, and it works fine, no problems of any sort. Then, a few days later, I installed the other module in my PowerMac, and immediately it started behaving very erratically: some programs didn’t open at all and others crashed with no warning, I tried to run Rember but it soon get stuck. I assumed the Ram module was faulty, emailed the dealer (who’s been very helpful) and then sent it back to get a replacement. The new module arrived yesterday, I installed it... and it was even worse: as some programs didn’t open as soon as the new module was installed, I rebooted the PowerMac but it hasn’t been able even to load the OS anymore, it just stopped at the blue screen forever, once came out a black screen and a Darwin login, but nothing else. As soon as I removed the Ram module the PowerMac started to work perfectly again.I'd assume again there's something wrong in the Ram module, but isn't it too much unlucky to get 2 faulty modules one after the other, or maybe the problem could somewhere else, in my PowerMac?!?
Unfortunately I can't test the new module in my father's machine, as we live 700 kms apart.
My hardware details are:
Power Mac G4
Model: PowerMac3,3
CPU: PowerPC G4 (2.9)
1 CPU
CPU Speed: 400 MHz
L2 Cache (per CPU): 1 MB
Memory: 896 MB
Bus speed: 100 MHz
Boot ROM Version: 4.2.8f1
thanks!

ok, I've now tried every possible combination... but with no success
First, taking out one of the "old" 128 MB I realized it was one of the High density DIMMs (chips on one side only) Japamac was mentioning, in total 2 of the 128 modules were like this. However, taking out one or both of them, or even having only the "new" 512 MB module in, hasn't changed much, sometimes the OS booted, sometimes not but there were always some programs not opening/crashing and Rember got stuck with an error message. With just the "new" module the booting stopped at the blue screen (only blue, no apple splash screen in the centre).
With the new module plus one of the old 128 MB modules (the one with chips on both sides) Rember got stuck very soon, and the error message was:
Memtest version 4.2 (32-bit)
Copyright (C) 2004 Charles Cazabon
Copyright (C) 2004, 2005, 2006 Tony Scaminaci (Macintosh ports)
Licensed under the GNU General Public License version 2 only
Mac OS X 10.4.11 (8S165) running in multiuser mode
Memory Page Size: 4096
System has 1 PPC processor(s) with Altivec
Requested memory: 434MB (455589888 bytes)
Available memory: 434MB (455589888 bytes)
Allocated memory: 434MB (455589888 bytes) at local address 0x02008000
Attempting memory lock... locked successfully
Partitioning memory into 2 comparison buffers...
Buffer A: 217MB (227794944 bytes) starts at local address 0x02008000
Buffer B: 217MB (227794944 bytes) starts at local address 0x0f946000
Running 1 test sequence... (CTRL-C to quit)
Test sequence 1 of 1:
Running tests on full 434MB region...
Stuck Address : setting 1 of 16testing 1 of 16setting 2 of 16testing 2 of 16
I guess all this confirm the "new" module is faulty, I'll soon email the dealer
Thanks to everybody for the help!

Mixing RAM modules on a 800Mhz machine

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