Potential memory problems for max GPU2 clients...

[torin3]

Ok, since I'm down a card in my work rig, I was looking over using this as a chance to switch it over to 9800 GX2 cards. I've got 4 PCI-E 16X sized slots (though when using them all, 3 of them are 8X speeds). However, I can only use 3 of them at one time due to the 4th one being a single-wide slot.

But as I was contemplating what 3 9800 GX2 cards could do in that machine, I remembered that I have 32bit Vista Business installed on this machine! :bang head I can't use 64bit for about another 3 months, due to software I need to run on this machine.

Now the reason this is a problem, is the for cards I had in the machine were 1 1/2gig and 3 1/4gig of RAM cards. That added up to 1 1/4 gigs, which left me about 2 Gigs of RAM available for other things.

But with the GX2 cards, they have a gigabyte of ram on each of them. After system overhead, that leaves me with less than 1 gig of RAM.

Crud!

I've thought of a short term solution, where I can run the software I need in a 32bit windows VM, but if the newer version that we are going to install in 3 months doesn't work with 64bit Vista, I'm going to be stuck, as it also doesn't work with Win2K....(Though I think I've got an extra WinXP retail disk, which should work....hmmm)

The trials of trying to max out production. Heat problems, empty wallet, OS problems. Uhg...

Thanks for listening. :beer:

[ChasR]

I fail to understand. FahCore_11 uses about 100 MB of memory. Running 6 instances would leave you with plenty of memory if you have 4 GB installed (3 recognized).

[torin3]

That is it though, the recoginzed portion. It isn't the amount of RAM FahCore_11 uses, it is how much is on the cards.

Currently, I've got 1 Gb of video ram in my system, over 3 cards.

This counts against my 4Gb limit. Here is what it is reporting as physical memory:

http://i166.photobucket.com/albums/u90/torin3/oc/memory.jpg

If it is only reporting 2046Mb, and I add another 2048Mb of Ram, that leaves me -2Mb in the hole.

And just to show that I don't have a dead stick I'm not aware of:

http://i166.photobucket.com/albums/u90/torin3/oc/memory2.jpg

So, I'm going to need to switch over to a 64bit OS if I'm going to have enough memory. Fortunately, I just got permission from my boss to do so. So, I'll be adding another 4 gigs in. I just hope there aren't any glitches...

[ChasR]

I don't think that's right (video memory deducted from addressable memory). The cpu can't address video memory so it doesn't count against the cpus total addressable memory. If you have 4 GB in the system, only 3 GB will be addressable by a 32 bit OS with or without video cards.

[torin3]

Well, I'm more than willing to be wrong on this one ;). Given that it would be a lot easier for me. I posted a question and a pointer to this thread in the MS OS subforum, so hopefully somebody who knows for sure will drop by and let us know. Not having to spend the day reinstalling the OS and software I use, and spending the extra money on RAM would make me a happy camper! :beer:

[ChasR]

I'm no expert at OS related matters. When I look at reported total physical memory, it varies from a low of 3.079 GB to a high of 3.406 GB on 3 XP rigs with the same 4 GB of memory and 512 MB vid cards. I have no idea why.

[VinnyTAMU]

Just thought I would post the same response here for everyone to see:

Taken from HP:

Microsoft Windows XP Professional, designed as a 32-bit OS, supports an address range of up to 4 GB for virtual memory addresses and up to 4 GB for physical memory addresses. Because the physical memory addresses are sub-divided to manage both the computer’s PCI memory address range (also known as MMIO) and RAM, the amount of available RAM is always less than 4 GB.
The PCI memory addresses starting down from 4 GB are used for things like the BIOS, IO cards, networking, PCI hubs, bus bridges, PCI-Express, and video/graphics cards. The BIOS takes up about 512 KB starting from the very top address. Then each of the other items mentioned are allocated address ranges below the BIOS range. The largest block of addresses is allocated for today’s high performance graphics cards which need addresses for at least the amount of memory on the graphics card. The net result is that a high performance x86-based computer may allocate 512 MB to more than 1 GB for the PCI memory address range before any RAM (physical user memory) addresses are allocated.

So the way that I interpret this is that if you have three GX2 cards installed at 1GB a piece you will have less than 1GB of physical memory left to address.

[ChasR]

Having read that, I now have the same interpretation as you and the explanation for the differences in reported physical memory on different machines with the same actual amount of physical memory. I've learned something, which is a good thing and harder to do than it used to be.

[Zerix01]

I would assume it would not allocate more than what is being used. So if you have 1GB on the card but only lets say 192MB's being used then only 192MB's of system memory will be reserved.

Any one know of utilities that tell you how much video ram is being used?

I wonder if this works this way on other platforms as well (Linux, Mac).

[Psykoikonov]

http://msdn.microsoft.com/en-us/library/aa366778.aspx

Facts

A 32 bit OS can only use 4GB of memory total, that means if you have 4GB of ram and your graphic card has 1GB of ram, you have a total of 5GB of memory.


Out of that 5GB of memory, you can only use 4GB total. 1GB the graphic card will take up, so now the 32bit OS can only use 3GB.

Enableing PAE, will limit to the OS to 2GB total. What PAE does is dedicate 2GB to OS and the other 2GB to anything other then the OS.

Vista 32bit can see only 3.5GB of ram total. The new sp1 only reports how much memory you have intalled, not how much memory you can use.

This means in Vista 32bit with 3 video cards having 1GB of Ram each the OS would have less than 512MB of system ram for itself.

http://www.microsoft.com/windows/windows-vista/get/system-requirements.aspx
or http://support.microsoft.com/kb/919183

Home Basic

1 GHz 32-bit (x86) or 64-bit (x64) processor

512 MB of system memory
Note On system configurations that use system memory as graphics memory, at least 448 MB of system memory must be available to the operating system after some memory is allocated for graphics.

20 GB hard drive with at least 15 GB of available space

Support for DirectX 9 graphics and 32 MB of graphics memory

DVD-ROM drive

Audio Output

Internet access (fees may apply)

Home Premium / Business / Ultimate

1 GHz 32-bit (x86) or 64-bit (x64) processor

1 GB of system memory

40 GB hard drive with at least 15 GB of available space

Support for DirectX 9 graphics with:

WDDM Driver

128 MB of graphics memory (minimum)

Pixel Shader 2.0 in hardware

32 bits per pixel

DVD-ROM drive

Audio Output

Internet access (fees may apply)

Which means it would not make min system requirements of even Home Basic (<512MB of Ram)

Very interesting read explaining Vista 32 bit memory limitations -> http://support.microsoft.com/kb/929605/en-us

Edit: I was aware of the 32bit Ram subtraction from other hardware before but this information sheds new light on the Vista 32 bit Ram limitations for me.

[torin3]

Well, I'll be ordering the cards today, and if they ship from NJ (did last time), I'll have them tomorrow and can find out for sure on Saturday what happens when you boot up windows with a negative memory allocation.... ;)

I'll be installing 64bit Vista Business right after, so it should be a no-harm no-foul situation.

[torin3]

Well, looks like I won't get to it this weekend. They are shipping it from TN, so it will be in on Monday. And I won't be able to get them all in until next Saturday

[StaTek]

You ordered 3 9800 GX2 cards? If so, 6 displays are going to give you trouble on Vista I think.

[torin3]

You ordered 3 9800 GX2 cards? If so, 6 displays are going to give you trouble on Vista I think.

What trouble is that? If I remember right, you have 3 of them on one of your systems, so you are definately the voice of experience.

Before, I had 8 displays on 4 cards and it wasn't causing me any problems. Only 4 of them had the desktop extended to them though.

Worst case, I'll move the 3rd one to my home system.

[StaTek]

Well please tell me what kind of luck you have with this. I could never get it to work on vista. When I was trouble shooting, I read a post by Tigerbiten that stated vista could go up to 8 monitors, but the HDMI outputs might be counting against that total.

[torin3]

Were you running 32 bit or 64 bit vista?

Also, when I'm using the GX2 card I have at home, only two monitors show up as options on Rivatuner.

However, if only 2 of them work, I'm no worse off, and I can upgrade one of my home rigs.

[StaTek]

Vista 64. Good Luck!

[torin3]

Well, they arrived about 10 minutes ago. I'm going to put two of them in now.

Doing some research it looks like XP and Vista are both supposed to support 10 displays. Well, we'll find out by this Saturday (when I've got the time to switch from 32 to 64 bit versions).

[torin3]

Oh, and I seem to be wrong about the memory. Maybe.

I switch from 1 GB of video memory in this system to 2 GB of video memory, and it is still showing 2 of the 4 GB installed system memory in the performance manager.

So...I'm wondering if since this board has 4 PCI-E 16X/8X slots if maybe they reserved 2 GB of address space in the BIOS so that if you ever did have 4 1/2GB video cards installed, it wouldn't mess anything up.

Or I could be entirely wrong on this, and it doesn't count video memory at all.

Though why would it show only 2GB in the performance tab in task manager, and show 4 GB in CPUZ even with only 1 GB of video ram installed?

More to ponder :bang head

[blakehenry00]

Is there something about memory remapping in the bios? I remember reading something about that.