But for all intents and purposes, it does apply to all 32bit OSes. Again, Linux using 36bit addressing mode does not suffer from this, but 32bit Linux in 32bit addressing mode and all 32bit versions of Windows behave the same way. It is all in the way the OS is designed, compiled and configured.

And that's good enough for me. Thanks for the information!

2000 Pro, XP x86, Vista x86, & Win 7 only support 4GB. I would think for the "ultimate" editions they could have licensed it for 8GB at least, but that is MS for you. You also have to go to server versions if you want more then 2 processors. Currently their licesing does not limit the number of cores a processor can have.

32bit Ultimate editions still have the same 32bit address space as their 32bit brethren. Microsoft will not change this for fear of breaking compatibility with existing apps.

Windows Home editions only support a single processor socket (single CPU). Windows Business, Professional and Ultimate can all use two CPUs with unlimited cores.

You need Windows Server for quad socket systems or higher. 64bit versions of Windows have varying support for RAM address space depending on the version used. Windows XP 64bit is limited to 128GB of RAM. Windows Vista Home 64bit and Windows 7 Home 64bit support 8GB. Windows Vista Business x64 and Windows 7 Professional 64bit support 16GB. Windows Vista Ultimate 64bit and Windows 7 Ultimate 64bit support 128GB of RAM.

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If they dropped the limitations I bet RAM prices would drop in a hurry and usher in the age of solid state HD's.

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Official Abuser of Boinc Buttons...
And no good credit hound!

This may be of interest:

http://msdn.microsoft.com/en-us/library/aa366778%28VS.85%29.aspx

Yes, that does help. I see they've changed the limits on 64bit Windows 7 to 192GB of RAM for all versions, and 128GB for most versions of 64bit Vista.

As you can see, all 32bit versions of Windows, including Vista and 7, can only address up to 4GB of RAM. There's the same discussion about PAE on that link that we're having here, and essentially they're saying the same thing I am: PAE does not make you use more than 4GB of RAM on a 32bit OS. The OS must be compiled for 36bit addressing, and that is only available in the Server versions of Windows 32bit.

Linux is still a different story. Most older 32bit distros did not have 36bit addressing enabled by default, but I'm told most newer 32bit distros have 36bit enabled by default.

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Well just got in from work and you guys have been busy.
I have read all the thoughts about memory addressing and the like.
Most of it went over my head LOL.
If I have to go to Win XP 64bit then I will.
This Rig on a Bench has now been running stock for about 24hrs and all is ok.
God its getting warm in here.
4 CPU's and 1 Very small GPU crunching Video card is a 9600GT 208 GFLOPS Peak,so not to hot.
RAC after 24 hrs is 215 so going up.
I have yet to set the max speed of the GEIL memory to 2133.
I cannot seem to find the relevent place to set it in the bios.
That is my next task and to OC the CPU a bit.

Dave

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Well just got in from work and you guys have been busy.
I have read all the thoughts about memory addressing and the like.
Most of it went over my head LOL.
If I have to go to Win XP 64bit then I will.
This Rig on a Bench has now been running stock for about 24hrs and all is ok.
God its getting warm in here.
4 CPU's and 1 Very small GPU crunching Video card is a 9600GT 208 GFLOPS Peak,so not to hot.
RAC after 24 hrs is 215 so going up.
I have yet to set the max speed of the GEIL memory to 2133.
I cannot seem to find the relevent place to set it in the bios.
That is my next task and to OC the CPU a bit.

Dave

From what was said your 4 cards with 896mb of mem will use up about 3.5gb of the 4gb you have installed leaving you with around 500mb for the OS to use. Which should in fact work.

It took me about 30 min to figure out how to set the memory speed to 1600 on my i7. I had to select a profile option instead of just setting the memory speed.

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From what was said your 4 cards with 896mb of mem will use up about 3.5gb of the 4gb you have installed leaving you with around 500mb for the OS to use. Which should in fact work.

Yeah, but he effectively has 6 GPUs, not 4.

Correct me if I'm wrong, but aren't 2 of those cards 295's? I believe each 295 has about 1.8 gig of ram apiece (896Mx2). (Each 295 is essentially a pair of 285's in one package.) Throw in the pair of 275's (at 896M each) and you're talking about 5.4 gig of video ram which is beyond the 4 gig limit even with no system memory at all!

On this MSI MoBo there are 6 places to save profiles.
There is also a whole list of memory options to change.
I realise that I need to changeTCL,TRCD,TRP and TRAS which I have done.
Still only getting 1600 showing instead of 2133.
I will have to do more reading.

Dave

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On this MSI MoBo there are 6 places to save profiles.
There is also a whole list of memory options to change.
I realise that I need to changeTCL,TRCD,TRP and TRAS which I have done.
Still only getting 1600 showing instead of 2133.
I will have to do more reading.

Dave

What I had to do for mine was find the section to set the memory profile. The machine I'm using right now at work as a similar setting for it's memory.



So in the bios I'd just have to set EPP 1.0 & all the other settings are changed automagicly.

My gigabyte board uses the term "profile" but yours could be diffrent.

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Further to the debate about memory usage with XP.
I have just put a second 9600GT into Rig on a Bench.
According to Task Manager PF Usage is 810 MB.
Both cards have 512 MB of mem.
Would that not mean that memory usage should be over 1 GB.
This is new stuff to me so please be gentle. LOL

Dave

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Further to the debate about memory usage with XP.
I have just put a second 9600GT into Rig on a Bench.
According to Task Manager PF Usage is 810 MB.
Both cards have 512 MB of mem.
Would that not mean that memory usage should be over 1 GB.
This is new stuff to me so please be gentle. LOL

Dave

Nope, task manager doesn't see video ram usage, only main memory.

GPU-Z will tell you how much video ram is being used, but that will give you the total amount in use, not the amount in use by BOINC.

Some BOINC CUDA tasks report some video ram usage information in the STDOUT, which you can view online by looking at the result after it's completed.

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I realise that but the debate earlier was that the video memory had to be shadowed.
I.E. if I put 4 video cards in this rig then the 6 GPU's will have to be shadowed.This will take up 5 gig of memory and XP can only shadow 4GB.
I have to go to XP64bit.
Not sure how it can shadow that amount of video mem as I only have 4 GB in the rig.
If that makes any sence.
I can't even find out how to configure my 2133 memory in the bios.
This AMI bios for this MSI rig is not as easy as the bios in my i7 rig,which was easy to set.

Dave

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Hi, what would happen, if you put 4 ATI 5770 (1GByte GDDR5) on a WIN XP x86 system, with 2 or 4GByte of RAM. Or equivalent nVIDIA card's

Maybe, not all the VIDEO-RAM would be used?!
Trying 1 5770 at Collatz and is doing well, in terms of RAC, that is.
(A Q6600 with 1 ATI HD5770 on WIN XP x86)

The other host has a 9800GTX+ and a QX9650 (@3.4MHz) and has a tenth of the RAC, compaired to Collatz.
Why so much of a difference, better to ask it at Collatz C ?

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You misunderstood. We weren't alking about shadowing.

Shadowing, specifically BIOS shadowing, was a technique used by DOS and early Windows computers (pre-Win95 IIRC) where the BIOS (Basic I/O System) ROM(s) weren't just used to boot the computer, but actually contained the software necessary to access the various devices in the computer, such as the disk drives.

ROMs are comparatively slow, as compared to RAM, so one technique to speed up the computer was to 'shadow' the BIOS ROM. This technique involved copying the BIOS ROM to a section of regular RAM, and then remapping that section of RAM to the same address as the BIOS ROM. The end result was the BIOS residing in RAM instead of ROM, which sped up disk access and screen writes.

The discussion here was about something completely different.

The video ram on a graphics card is additional memory included on the card. It doesn't replace the ram on your motherboard.

[The next paragraph is a summary of what everyone has said in this thread -- I'm not personally familiar with how current generation video cards get mapped, so any errors below are in my interpretation of what others have said. Take it with a grain of salt. :) ]

What's been said here is that the video ram, in addition to be being accessible by the GPU cores on the graphics card, also takes up address space in the main CPU's address space. The CPU sees both the main motherboard memory (which it uses for all of it's work) and the video memory, which it uses only for communicating with the video card. Thus, Windows needs to be able to address the SUM of both the motherboard and video memory, and your 6 graphics cards (the 295s count double) occupy too much space to work with a 32 bit version of Windows. As you add graphics cards, the cards's memory forces Windows to ignore some of your regular memory because 32 bit Windows is only allowed to see a total of 4 gig. With 64 bit Windows, this isn't a problem because Windows can see more than 4 gigs.

I hope that's a clear explanation, and I also hope I got it all correct.

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If a video cards memory is mapped to the system memory space making it unusabealbe for the system. Then wouldn't the system requirments for say a BFG NVIDIA GeForce GTX 285 OC 2GB card be more then 2GB. Also wouldn't they mention the requirements of needing more system memory when listing the SLI requirments. Also the SAPPHIRE HD5970 2GB GDDR5 PCIE lists in it's system requirments that the system only requires 1GB.

I think a lot of what was said must be based on long out of date information.

EDIT: Worth noting is that 6 of the top 20 computers are using x86 OS's. Some of those machines are listed as having only 2GB of ram & displaying [4] NVIDIA GeForce GTX 260 (895MB). While those systems may not have 4 295's some of them might.

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I realise that but the debate earlier was that the video memory had to be shadowed.
I.E. if I put 4 video cards in this rig then the 6 GPU's will have to be shadowed.This will take up 5 gig of memory and XP can only shadow 4GB.
I have to go to XP64bit.
Not sure how it can shadow that amount of video mem as I only have 4 GB in the rig.
If that makes any sence.
I can't even find out how to configure my 2133 memory in the bios.
This AMI bios for this MSI rig is not as easy as the bios in my i7 rig,which was easy to set.

Dave

What's the model of the board? I could download the manual & give it a peek if you wanted another set of eyes.

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If a video cards memory is mapped to the system memory space making it unusabealbe for the system. Then wouldn't the system requirments for say a BFG NVIDIA GeForce GTX 285 OC 2GB card be more then 2GB.

You're confusing "memory space" (aka address space) and memory. They're very different things.

What was said was that the video memory takes up "address space". It doesn't displace (or 'shadow') main memory. It just shares the same address space.

If that doesn't make sense, then just accept that no, you do NOT need physical RAM equal to the amount of video RAM. Nobody here said that, and that is certainly not true.

You can run a GTX295 with nearly 2 gigs of video ram in a system which only has 1 gig of regular ram. There's no problem doing that.

The problem is that the SUM of the video ram PLUS the main ram can not exceed 4 gigs under 32-bit Windows. That's the only limitation here.

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If a video cards memory is mapped to the system memory space making it unusabealbe for the system. Then wouldn't the system requirments for say a BFG NVIDIA GeForce GTX 285 OC 2GB card be more then 2GB.

You're confusing "memory space" (aka address space) and memory. They're very different things.

What was said was that the video memory takes up "address space". It doesn't displace (or 'shadow') main memory. It just shares the same address space.

If that doesn't make sense, then just accept that no, you do NOT need physical RAM equal to the amount of video RAM. Nobody here said that, and that is certainly not true.

You can run a GTX295 with nearly 2 gigs of video ram in a system which only has 1 gig of regular ram. There's no problem doing that.

The problem is that the SUM of the video ram PLUS the main ram can not exceed 4 gigs under 32-bit Windows. That's the only limitation here.

Ok right, address space not ram, got it. Think I got that mixed up when someone mentioned something along the lines of 4 896MB cards would use 3.6GB of the 4GB space leaving 400MB for the OS.

Am am rather curious now as to how a system would respond in such a situation.

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@ Michael thanks for making that synopsis of the memory debate more enlightening.
I think I got the jist of it now.As Hal pointed out about top hosts not sure how they get round it.

@ Hal thanks for the offer any help to set this memory up would useful.
The MoBo is an MSI 790FX-GD70 which supports 2133 memory.
I have 4GB of GEIL DDR3 PC3 17000 2133MHz CL 9-9-9-28.
If that helps.I have looked on the net for info how to configure but no joy yet.

Dave

PS Rig on a Bench RAC now 673 LOL but there are 2 9600gt's helping out.They were surplus

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