VOGONS


First post, by villeneuve

User metadata
Rank Newbie
Rank
Newbie

Hello,
I'm currently working on a build for Windows XP gaming but the same machine is supposed to also run the 64 bit editions of Windows 7 and Linux and therefor I'd like to install 8 GB of RAM in the machine.
Of course I know that Windows XP 32 bit would only see up to 4 GB of RAM, but wonder if running more RAM than that will cause any issues in terms of stability and/or performance and if that's the case if there are any tricks/workaround/tweaks I should apply?
Thanks for reading!

Reply 1 of 24, by dionb

User metadata
Rank l33t
Rank
l33t

You won't be able to use 4GB RAM, 4GB is the total addressable space with 32b, which means both RAM and things like video memory. If you have a high-end GPU with lots of RAM that will eat heavily into the 4GB. I don't know what happens with GPUs with >4GB RAM, but one way or another you'll end up with (a lot) less than 4GB actually usable. It's possible a GPU with less RAM will actually improve matters with 32b Windows.

Reply 2 of 24, by DosFreak

User metadata
Rank l33t++
Rank
l33t++

Populating all memory slots may make the northbridge run hotter.
Use the proper timings and test your memory.
As mentioned above you'll only have <4GB usable.

DOSBox Compilation Guides
DosBox Feature Request Thread
PC Game Compatibility List
How To Ask Questions The Smart Way
Running DRM games offline

Reply 3 of 24, by red-ray

User metadata
Rank Oldbie
Rank
Oldbie
dionb wrote on 2020-03-04, 13:22:

You won't be able to use 4GB RAM, 4GB is the total addressable space with 32b, which means both RAM and things like video memory.

There is a patch for XP-32 that enables > 4 GB to be used, see https://msfn.org/board/topic/176356-simple-xp … -true-pae-guide, but I have never used it as instead I use 2003 Enterprise Server which actually supports 8 GB.

I have XP-32 on my 12.00 GB Gulftown system and it runs fine, but only uses 2.50 GB as the system has 3 x GTX 680.

Reply 4 of 24, by villeneuve

User metadata
Rank Newbie
Rank
Newbie

Thanks for your replies although the first two didn't answer my question 😉

@red-ray: your reply makes me confident that it's not an issue running XP 32 with more than 4 GB of RAM installed. I'll checkout that patch also.

Btw I have a 3 GB and a 6 GB GPU ready to put into that system so I'll find out how Windows XP behaves with those two. I never tried it before so I'm looking forward to that.

Greets!

Reply 5 of 24, by red-ray

User metadata
Rank Oldbie
Rank
Oldbie
villeneuve wrote on 2020-03-04, 14:00:

Btw I have a 3 GB and a 6 GB GPU ready to put into that system so I'll find out how Windows XP behaves with those two.

It's not the amount of RAM that GPUs have that matters, it's the amount of address space they use.

I found the SIV save file from a patched W7-32 system with 6GB, it has 3 x GPUs with 512MB, but they only look to use 256MB of address space.

Edit: Oops, I just noticed it's W7-32, but XP-32 would be much the same.

Attachments

  • XP-32 using 6GB.png
    Filename
    XP-32 using 6GB.png
    File size
    225.99 KiB
    Views
    688 views
    File comment
    W7-32 system with 6GB
    File license
    Public domain
Last edited by red-ray on 2020-03-04, 15:01. Edited 1 time in total.

Reply 6 of 24, by villeneuve

User metadata
Rank Newbie
Rank
Newbie

It's not the amount of RAM that GPUs have that matters, it's the amount of address space they use.

Yes, but, correct me if I'm wrong here, the more VRAM a GPU has the more address space it'll use.

Reply 7 of 24, by Falcosoft

User metadata
Rank Oldbie
Rank
Oldbie

32-bit WinXP has no problem with more than 4GB installed RAM. Red-ray is right, the maximum available memory under 32-bit Windows is determined by the lowest starting address of any video card's linear frame buffer not by the amount of Video RAM.
Starting address of LFB:
0xC0000000 -> 3GB available
0xD0000000 -> 3.25GB available
0xE0000000 -> 3.5GB available
You can test this by checking the used memory resources of your VGA in device manager.
If you have 2 active modern VGA the available RAM would be less than with only 1 because the system has to reserve 2 LFB regions.
So even under a 32-bit OS you can use cards with 2/4 GB of Video RAM since addressing full video RAM is a concern of the driver. On the CPU side there's usually only a 256MB area in the PCI address space. The same is true for 2 cards.
Regarding video memory handling and the 256MB area: an analogy could be that under pure 16-bit real mode DOS that has an address limit of only 1MB you can use the full VGA frame buffer (8/16/32 MB etc.) through VESA driver/BIOS calls by using a 64KB area (A0000 - AFFFF) and bank switching.

Also it is worth mentioning that you can use the unused RAM under XP for ramdrive. You can even put the pagefile on it.
For this to work you need special ramdrive software that supports PAE and can use the RAM not used by XP. In case of Gavotte Ramdisk Utility you should add UsePAE=1 to registry manually or by using the included ram4g.reg file.
https://www.megaleecher.net/ramdisk
https://www.megaleecher.net/uploads/rramdisk.zip

Yes, but, correct me if I'm wrong here, the more VRAM a GPU has the more address space it'll use.

No, it's only true in case of cards with less than 256MB of onboard RAM . Apparently no card uses more than 256MB address space even it has 2/4 GB of onboard VRAM.
But the point is the available max. RAM under 32-bit OS is not directly dependent even on the amount of used address space but the starting address of the card's LFB.
So even if your card has only 64MB VRAM and the used address space is only 64MB but its LFB has a starting address of 0xC0000000 then you will only have 3GB available RAM under 32-bit WinXP.
While if you have an 1GB card that uses 256MB address space but its LFB starting address is 0xD0000000 then you will have 3.25GB available RAM.

Website, Facebook, Youtube
Falcosoft Midi Player + Munt VSTi + BassMidi VSTi topic

Reply 8 of 24, by red-ray

User metadata
Rank Oldbie
Rank
Oldbie
villeneuve wrote on 2020-03-04, 14:39:

It's not the amount of RAM that GPUs have that matters, it's the amount of address space they use.

Yes, but, correct me if I'm wrong here, the more VRAM a GPU has the more address space it'll use.

The amount of VRAM and the amount of address space are not really related, for example an RTX 2080 Ti has 11GB and an RTX 2080 has 8GB and both use the same amount of address space which is 256KB + 32MB + 256MB

Reply 9 of 24, by spiroyster

User metadata
Rank Oldbie
Rank
Oldbie

It's only GPU mapped memory that would fall under this restriction. The GPU is an ecosystem in itself and neither GL or DX applications have direct access to its memory, so a 32-bit program will not be restricted to the 4GB limit in VRAM. Applications have handles to the GPU resources (unless the VRAM is mapped, which is slow and is only done is the program wants to manipulate the data directly without upload through the API), so 32-bit applications could theoretically max a GPU with >4GB VRAM and still work no problemo.

Reply 10 of 24, by matze79

User metadata
Rank l33t
Rank
l33t

As there are no longer Updates, you also can Patch kernel for PAE and run with any amount you want.
I run Windows XP with 8Gb RAM, but there are some limitations.
Some Drivers won`t work in PAE Mode.
And a process only can use 2Gb at once.

https://dosreloaded.de - The German Retro DOS PC Community
https://www.retroianer.de - under constructing since ever

Co2 - for a endless Summer

Reply 11 of 24, by Tiido

User metadata
Rank Oldbie
Rank
Oldbie

I run 8GB with PAE hack and a set of new drivers for some internally supported hardware classes and things work without problems on the target machine (Thinkpad X200t). I used to have issues with USB webcams and storage devices prior to finding a version of the PAE stuff with updated base drivers.

T-04YBSC, a new YMF71x based sound card & Official VOGONS thread about it
Newly made 4MB 60ns 30pin SIMMs ~
mida sa loed ? nagunii aru ei saa 😜

Reply 12 of 24, by agent_x007

User metadata
Rank Oldbie
Rank
Oldbie

If anyone is curious... Titan Black "takes" 256MB from available RAM pool :

3DMark 06 stock.PNG
Filename
3DMark 06 stock.PNG
File size
466.08 KiB
Views
614 views
File license
Fair use/fair dealing exception

While Titan X(M) "takes" 512MB :

Titan X mini.png
Filename
Titan X mini.png
File size
373 KiB
Views
614 views
File license
Fair use/fair dealing exception

108080818886.png

Reply 13 of 24, by matze79

User metadata
Rank l33t
Rank
l33t
Tiido wrote on 2020-03-04, 17:10:

I run 8GB with PAE hack and a set of new drivers for some internally supported hardware classes and things work without problems on the target machine (Thinkpad X200t). I used to have issues with USB webcams and storage devices prior to finding a version of the PAE stuff with updated base drivers.

yeah basicly you take win2003 drivers and use them on XP

https://dosreloaded.de - The German Retro DOS PC Community
https://www.retroianer.de - under constructing since ever

Co2 - for a endless Summer

Reply 14 of 24, by red-ray

User metadata
Rank Oldbie
Rank
Oldbie
matze79 wrote on 2020-03-04, 16:08:

And a process only can use 2Gb at once.

Incorrect, you can boot with /3GB and should be able to use 3GB, but this limits the total to 16GB, see https://support.microsoft.com/en-gb/help/2830 … 3-and-in-window, but I am unclear as to if this is possible on XP.

Further for 32-bit programs to use more then 2GB they need to be linked with /largeaddressaware which means they can use 4GB on x64 + ia64 editions of Windows.

Update: I booted a W2K-AS system with /PAE /3GB and the memory is now 7.75GB and SIV used about 3GB of virtual address space. Given this I am pretty sure 3GB will be possible on XP-32.

file.php?id=78246

Attachments

  • RXY-3GB.png
    Filename
    RXY-3GB.png
    File size
    49.56 KiB
    Views
    534 views
    File license
    Public domain
Last edited by red-ray on 2020-03-04, 23:54. Edited 2 times in total.

Reply 15 of 24, by red-ray

User metadata
Rank Oldbie
Rank
Oldbie
agent_x007 wrote on 2020-03-04, 17:21:

While Titan X(M) "takes" 512MB

No it doesn't and I can't see how the screen shots you posted indicate it does. The prefetch area is 288 MB so there is no way it uses 512 MB!

file.php?id=78223

Attachments

Reply 16 of 24, by hwh

User metadata
Rank Member
Rank
Member
Falcosoft wrote on 2020-03-04, 14:58:
32-bit WinXP has no problem with more than 4GB installed RAM. Red-ray is right, the maximum available memory under 32-bit Window […]
Show full quote

32-bit WinXP has no problem with more than 4GB installed RAM. Red-ray is right, the maximum available memory under 32-bit Windows is determined by the lowest starting address of any video card's linear frame buffer not by the amount of Video RAM.
Starting address of LFB:
0xC0000000 -> 3GB available
0xD0000000 -> 3.25GB available
0xE0000000 -> 3.5GB available

What determines this? Hardware choice? Card choice? Driver?

Reply 17 of 24, by red-ray

User metadata
Rank Oldbie
Rank
Oldbie
hwh wrote on 2020-03-04, 22:00:

What determines this? Hardware choice? Card choice? Driver?

The windows driver will not have any effect, it's a combination of which cards you have and how the BIOS set's things up.

Reply 18 of 24, by pentiumspeed

User metadata
Rank Oldbie
Rank
Oldbie

Hi there, I did install XP on a Dell optiplex 990 i7-2600 with 8GB installed. XP sees as 3.5GB. No problems.

Cheers,

Great Northern aka Canada.

Reply 19 of 24, by agent_x007

User metadata
Rank Oldbie
Rank
Oldbie
red-ray wrote on 2020-03-04, 18:14:
agent_x007 wrote on 2020-03-04, 17:21:

While Titan X(M) "takes" 512MB

No it doesn't and I can't see how the screen shots you posted indicate it does. The prefetch area is 288 MB so there is no way it uses 512 MB!

Well, when I swap GPU from Titan Black to Titan X(M), my available RAM drops to 2,94GB (can be seen both in task manager and under System information), and when I swap back to Titan Black I get 3,44GB back again.

When get to PCIe with XP again, I will test this with Your program under XP.

108080818886.png