4GB Ram problem

[thunderkiss666]

ive installed 2 kits of 2x 1GB of Corsair Dominator 8500 , i am using a Asus Striker II formula mobo, i have two problems

1- when i have installed 4 sticks of 1Gb modules, my mobo says it does not detect SLI ready memory
2- i am running vista ultimate 32bit, from my computer properties it displays 4Gb of ram installed, but when i run everest it shows that only 2301Mb of usable physical memory is available. i have also enabled PAE on vista but the problems persists

could anyone shed some light on this please. thanks

 

[Nothinman]

i have also enabled PAE on vista but the problems persists

And it will continue to persist until you upgrade to Vista64 or another OS that isn't crippled like 32-bit Windows clients.

 

[myocardia]

Welcome to anandtech, thunderkiss. To answer your questions, 1) That isn't a problem, there's no such thing as SLI-ready memory 2) That is a problem, with all 32-bit OS's. The reason is that a 32-bit OS only has ~4GB of usable address space. The big problem with that is that the OS has use (subtract) alot of things from that space, including ~ ½GB for the motherboard, because of things like onboard USB ports, PCI slots, PCIe slots, onboard networking ports, and a host of other things.

That leaves only ~3.5GB, which would be fine, except for the fact that each video card requires an additional 256 MB of address space-- that's why I have ~3.25GB left, out of 4GB, with my single 8800GT. The people who it really screws, though, are people like you who have 4 video cards, since that's 1GB being used, just for video cards. And like Nothinman already said, the only solution to the problem is to upgrade to a 64-bit OS.

 

[Nothinman]

That is a problem, with all 32-bit OS's.

No, it's a problem with 32-bit Windows client OSes. If you install 32-bit Win2K3 Server Enterprise you'll get all of your memory, up to 8G is I think where MS decided to cut it off. The same is true if you install 32-bit Linux, FreeBSD, OpenBSD, etc.

 

[thunderkiss666]

that makes a lot of sense to me, i am using a quad sli rig, since 3.5gigs r available as usable memory, and then since quad sli = 4 gpu`s, since you say each gpu will take 256mb, so 4x 256Mb= 1 gig, so now it all makes sense. now i know why everest displays my available memory as 2.4Gigs. i will take your advice and upgrade to vista 64bit, would not be a problem since all my hardwares are vista certified and i have downloaded all the 64 bit drivers. once again many thanks for the clarification myocardia

 

[Nothinman]

since you say each gpu will take 256mb,

Each GPU should take as much memory as it holds. So if the card has 256M it'll take 256M but if it has 512M it'll take 512M.

 

[myocardia]

Originally posted by: Nothinman
No, it's a problem with 32-bit Windows client OSes. If you install 32-bit Win2K3 Server Enterprise you'll get all of your memory, up to 8G is I think where MS decided to cut it off. The same is true if you install 32-bit Linux, FreeBSD, OpenBSD, etc.

Haha, I actually knew that. That was actually supposed to say "with all 32-bit Windows OS's". I had forgotten that it didn't apply to Server 2003, though.

Originally posted by: thunderkiss666
thanks for the clarification myocardia

You're very welcome.

Originally posted by: Nothinman
Each GPU should take as much memory as it holds. So if the card has 256M it'll take 256M but if it has 512M it'll take 512M.

That's not true at all. Address space and card memory are two different things. If you don't believe me, feel free to dig around in the Video archives for the long post where BFG10K explains why, citing references. It was ~6 months ago, IIRC.

 

[Nothinman]

That's not true at all. Address space and card memory are two different things. If you don't believe me, feel free to dig around in the Video archives for the long post where BFG10K explains why, citing references. It was ~6 months ago, IIRC.

For AGP you only lose the size of the GART but I was under the impression that with PCIE the entire set of video memory was directly mappable and thus took address space.

 

[myocardia]

I have to leave now, but if you can find that thread, it has the definite answer in it. And, after thinking further about it, (the thread had two people arguing over which of their hypotheses was right), the answer was one of these two things: either it's only 256MB per card, or only half of your VRAM counts against you, because of the way that AFR works (whether it's SLI or Crossfire). If it were total VRAM, then thunderkiss would only have ~1.5GB of RAM left, since he's got 4x512MMB cards. I'll look for that thread later this evening, if you don't want to look for it.

edit: Okay, search isn't working tonight, at least for the archives. I've been trying for >2 hours. I'll do my best to try to remember to do it tommorrow, among the other things I'll be doing.

 

[pallejr]

The address map provided by msinfo32 or device manager can tell exactly how the address space is populated

 

[n7]

The amount of memory "lost" isn't based on vRAM, it's a set amount of address space, nearly always 256 MB, though rarely 512 MB.

I know the posts/thread you are talking about myocardia; i found it interesting as well.

The OP is "losing" 1 GB due to the four GPUs he has, & the rest is "lost" on other devices.

A 64-bit OS would indeed make sense in this situation.

 

[n7]

Hah, you're gonna hate me myocardia.

I knew it was Peter who explained how it's calculated, so i found the thread with one search
http://forums.anandtech.com/me...keyword1=address+space

In there, he expains how much gets allocated for video cards, amongst other things.

 

[myocardia]

Originally posted by: n7
Hah, you're gonna hate me myocardia.

I knew it was Peter who explained how it's calculated, so i found the thread with one search
http://forums.anandtech.com/me...keyword1=address+space

In there, he expains how much gets allocated for video cards, amongst other things.

No, I don't hate you, I'm grateful you found it. I've spent the better part of yesterday looking for that thread, and still hadn't found it. Of course, I was searching using BFG10K as one of the words being searched for, so I would never have found it. Thanks, now it's bookmarked.