Adding dual-channel memory

[ekatsumata]

I do lots of Photoshop work, and I'd like to add more memory to my system as I've been working on larger and larger files.

Currently, I have 2x1GB DDR400 Corsair memory sticks running in dual-channel in my system. I'd like to add another 2x1GB for a total of 4GB. Does the new pair of memory sticks need to match my original pair to maintain dual-channel mode? Or can I add a different pair of sticks?

If I recall correctly, the pair in my system is Corsair ValueSelect. Would it be a problem to add a pair of say, Crucial?

Also, how do I tell if my processing speed is memory-limited? In other words, I'd like to know if adding more memory will speed things up.

My system consists of a GIGABYTE GA-K8N Pro-SLI Socket 939, AMD Athlon 64 X2 3800+, PNY GeForce 6600GT 128MB, and the two sticks of 1GB DDR-400 Corsair memory mentioned above. I am running Windows 2000, but plan to upgrade to either XP or Vista sometime soon -- haven't decided yet.

Thanks in advance.

 

[Nickel020]

You can never really tell if RAM sticks from different manufacturers will work together until you actually try it out. This is why many retailers allow you to easily return RAM modules. You can actually not even tell if a certain RAM stick works on a certain motherboard at all unless you try it (or find a compatability list, but there would be too many combinations for compatability lists of two different types of modules with all kinds of motherboards). You can't even be sure if the same model number Corsair RAM will work since they use different memory chips for value RAM depending on when it was manufactured.

I think the RAM itself will actually run slower though, IIRC correctly with 4 modules installed you can only run them at a command rate of2T instead of 1T . Also if they're both double-sided they might only run at DDR333 instead of DDR400.

As for knowing whether you need more RAM or not, if the page file usage in the task manager -->performance is higher than your total RAM, then more RAM is gonna bring more performance (check this while using photoshop of course).

Your best bet is probably to take your PC to a local retailer and try different RAM to see if it works.

 

[gOJDO]

1. To avoid any problems, use same memory modules. There are always problems with s939, when you use both one-sided and two-sided types of DDR RAM modules. Your system might recognize only half of the memory you have, work as single channel or a combination of both.
2. To find out if your system is bottlenecked by the lack of RAM, you have to check out how much RAM is available to the system when you are doing your most intensive tasks. Open task manager and watch the Performance tab. If Available Physical Memory is above 100MB while you do your most intensive tasks, then you have enough RAM.
3. If you have a lot of huge documents opened at same time, then it is possible that more RAM will improve the performance. IMO your processing speed is limited by your CPU.

 

[Boyo]

I would not go with 4GB of memory. As Nickel states, your command rate will default to 2T and your RAM will run as DDR333. Instead, you should look to see if there is a better set of RAM modules that will run better and faster than your Value Select.

 

[SimMike2]

I have two completely different matched pairs - 2 DDR400 1GB, 2 DDR333 512MB - and it works perfectly fine in my Biostar 939 board. I run it at 179 memory speed, but it does run at CAS 2 at this setting. In my opinion, CPU speed is king, not memory speed. Also, I think the benefit of going to 3GB as opposed to 2GB outweighs the drop in bus speed.

 

[BassBomb]

Originally posted by: Boyo
I would not go with 4GB of memory. As Nickel states, your command rate will default to 2T and your RAM will run as DDR333. Instead, you should look to see if there is a better set of RAM modules that will run better and faster than your Value Select.

it only runs at DDR333 on older revisions. Venice and up can do 4 sticks @400mhz (2T)

 

[Nickel020]

That depends on the motherboard as well, not only what revision the CPU is.

 

[ekatsumata]

think the RAM itself will actually run slower though, IIRC correctly with 4 modules installed you can only run them at a command rate of2T instead of 1T . Also if they're both double-sided they might only run at DDR333 instead of DDR400.

So if the actual RAM is slower, how much will it affect my performance? I was under the impression that really fast RAM is important for games, but not so much for other tasks.

As for knowing whether you need more RAM or not, if the page file usage in the task manager -->performance is higher than your total RAM, then more RAM is gonna bring more performance (check this while using photoshop of course).

When you say page file, are you referring to the MEM Usage in Task Manager? If so, the MEM Usage often hits over 2GB, so I assume that this means more RAM will help?

2. To find out if your system is bottlenecked by the lack of RAM, you have to check out how much RAM is available to the system when you are doing your most intensive tasks. Open task manager and watch the Performance tab. If Available Physical Memory is above 100MB while you do your most intensive tasks, then you have enough RAM.
3. If you have a lot of huge documents opened at same time, then it is possible that more RAM will improve the performance. IMO your processing speed is limited by your CPU.

I was just working on a number of files on in two different apps, and found that my Physical Memory in Task Manager dropped down to 5MB!!! I guess more RAM will help.

I often do have several huge docs open at the same time, and I just realized that a 100MB Photoshop file can easily be several times that while being worked on due to the fact that Photoshop stores several history states of that file until the file is closed. So it seems having a couple of 100MB files open in Photoshop can easily seem to utilize 2 GB of memory.

So I guess I'm back to trying to figure out which memory sticks to buy. I'll probably look for the same kind I already have and make sure that they're returnable.

Thanks to everyone for the replies! Some of it was a bit over my head but gave me a good base to do some further research.

 

[sandorski]

32 bit Windows OSes only allow 2gb of ram per Application, so you should consider getting a 64bit version of Windows if you're going to 4gb.

 

[Rottie]

I have 4 stick of dual channel ddr400 and I checed it runs at 400mhz speed with 2T. I believe if you have Winchester core it will runs at 333mhz speed.

 

[Ahill]

Originally posted by: Nickel020


I think the RAM itself will actually run slower though, IIRC correctly with 4 modules installed you can only run them at a command rate of2T instead of 1T . Also if they're both double-sided they might only run at DDR333 instead of DDR400.

Guys have a Chaintech nf4 ultra board. I slapped two more sticks of Mushkin (2.5 CL stuff) the other day and my settings stayed at 1t and DDR 400. At first I did not believe it myself. Not to go into a long explanation but I had another set of 2 x512mb Blueline and it would always default to 2T and DDR 333 when I put it into this board.

I ran CPUz and it also said I was at 1T. Not to hijack this thread but does anyone know why this is? If there is a reason maybe ekatsumata could make it work too.

 

[Nickel020]

Ekatsumata, you could also take a look at the RAM chips on your RAM and if they're not re-labeled by Corsair (i.e. they're not saying Corsair but Samsung, Infineon, Micron etc.) you can try to get Corsair Value Select with exactly those chips, which should have a high chance of working.
As far as I know they might be Micron or Samsung, and probably other chips as well. Usually the end ot the long serial number tells you what kind of chips they are. Micron should be 5B-D, Samsung should end with UCCC.

 

[stevty2889]

Originally posted by: sandorski
32 bit Windows OSes only allow 2gb of ram per Application, so you should consider getting a 64bit version of Windows if you're going to 4gb.

Yep, going to 4 gig with a 32bit OS isn't going to let you use all 4 gig, programs are limited to 2gig(although there is a workaround for some programs) and windows will only give you access to 3.25gb of it anyway.

 

[ekatsumata]

Thanks for the replies. And thanks for reminding me of the 2GB limit per application in 32-bit Windows. In any case, I do quite a bit of multi-tasking, using multiple apps simultaneously, so being able to dedicate a full 2GB of memory to Photoshop might be beneficial.

As for 64-bit Windows, I really considered it when I built my current system. There still seems to be some driver issues, and I don't really want to spend my time dealing with bugs.

Hmmm, access limited to 3.25GB? That's news to me. I just googled around and came across several sites describing this. Still, I might upgrade, as the additional 1.25GB should be helpful. Almost seems like a waste to get 2x1GB...

Thanks again!

 

[ekatsumata]

I got another pair of DDR400, exact same model number, and this new pair works fine by itself, it doesn't play so nicely with my existing pair.

With all four sticks in, Windows does boot up, and it recognizes 3.25GB in dual-channel mode. I'm able to surf the internet and such, but once I open up Photoshop or Lightroom and do something a bit more demanding, the system hangs up. Oh well, time to return the new set.

Thanks for the replies.

 

[myocardia]

That's because you have your Command Rate locked at 1T, I'd be willing to bet.

 

[Rottie]

Originally posted by: BassBomb

Originally posted by: Boyo
I would not go with 4GB of memory. As Nickel states, your command rate will default to 2T and your RAM will run as DDR333. Instead, you should look to see if there is a better set of RAM modules that will run better and faster than your Value Select.

it only runs at DDR333 on older revisions. Venice and up can do 4 sticks @400mhz (2T)

that's correct in fact I had all 4 sticks runs at 400mhz 2T with a64 3500+ venice core before. now with Toledo X2 core running at same 400mhz 2T.

 

[ekatsumata]

Originally posted by: myocardia
That's because you have your Command Rate locked at 1T, I'd be willing to bet.

I just checked, and my command rate is 2T. I reinstalled the 2 additional sticks, and still 2T. I found a setting called "MEM Remap (4G support)" and enabled it, which seemed to work for a few minutes before I got a blue error screen stating that "An attempt was made to execute non-executable memory," whatever that means

I'll be RMA'ing the memory this week, unless someone has another suggestion.

Thanks for the replies so far.

 

[myocardia]

Before you send it back, try upping your vdimm by .1v and your vcore by one notch. As a matter of fact, give your RAM 2.8v of vdimm. Also, raise your RAM's timings slightly. Like if it's 2.5-3-3-7 RAM, try 3-3-3-8 2T.

 

[Cardio]

You will not get 4GB of mem usage with Win 2000 or XP, will see it but only use 3GB. Different Vista versions can use different amounts of ram also, be aware when you upgrade.

 

[ekatsumata]

Originally posted by: myocardia
Before you send it back, try upping your vdimm by .1v and your vcore by one notch. As a matter of fact, give your RAM 2.8v of vdimm. Also, raise your RAM's timings slightly. Like if it's 2.5-3-3-7 RAM, try 3-3-3-8 2T.

Thank you very much for the reply. I did the following:

1. I upped my vdimm by 0.1v.
2. I left my vcore alone -- it's set to "normal" and because I'm not really sure what the normal voltage is, I have no point of reference for "one notch."
3. I couldn't figure out how to give my RAM 2.8v of vdimm.
4. My ram is of the "value" variety, which is 3-3-3-8. In BIOS, I manually set the timings to 3-3-3-9 2T.

I really don't understand the "why" for these settings, but my system seems to be stable now with all four sticks installed. Windows is seeing 3.25GB, which is what I expected. I opened some large files in Photoshop, played around a bit, opened Google Earth in the background while burning a DVD and it all seems to work fine now.

Some more questions...

Somehow, my system seems slower -- could this be due to the settings I changed? Or maybe it's just my imagination (I'll do some tests this weekend).

The only changes I made above are #1 and #4 above. Would I lose stabiliity by setting #4 back to it's default settings? I suppose I could test this, but I don't want to fry anything.

Thanks again for the help. Much of this information is way over my head, but googling around seemed to help. I guess I don't have to RMA these sticks after all

 

[myocardia]

Well, since your RAM is 3-3-3-8 RAM, I'd put your timings @ 3-4-4-8, then run Orthos on the Blend test overnight, to make sure it's actually stable. And yeah, as strange as it sounds, it's normal for it to seem/be slower when you double the RAM, at least with normal use, like in Windows, web browsing, etc. You'll get used to it. I was amazed that moving from 1GB to 2GB was slower, especially since I didn't have to change my RAM's timings any at all.

edit: And what do you mean you can't figure out how to change your vdimm to 2.8v? You said you upped your vdimm by .1v. If you know where to change it, then you know where to change it.

 

[ekatsumata]

I'll try out those timings you suggest. I have no idea what Orthos or the Blend test is, but I'll look into it this weekend when I hopefully have some time.

As for setting the VDIMM to 2.8v...
There's a setting in my BIOS called "DDR Voltage Control" with three settings:
> Normal (default)
> +0.1v
> +0.2v

There was no such option for an absolute setting (e.g. 2.8v), only those options listed above. The specs for my memory sticks list a voltage of 2.3v - 2.7v. So I guess setting +0.1v makes the memory 2.4v - 2.8v? These memory specs are all new to me! I've built a few systems before but never dealt with memory timings! Sorry for the newbie questions

Thanks for the suggestions. I'm just happy that my system seems to be working fine with all of the memory. Though my system seems slower, Photoshop seems to be hitting the scratch disk much less frequently now. I'll probably do some tests running batches of typical Photoshop actions with and without the new memory, and with the timings you suggested above.

Have a great weekend!