Computers & Electronics

System RAM + VRAM limits in older PCs

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System RAM + VRAM limits in older PCs

Just wondering if the limits on the total combined amount of system RAM and VRAM still applies to older computers (whether it was 32 bit or 64 bit)? They did in Windows Vista/7 (e.g., if maximum RAM was 4 GB and you had that installed, and 1 GB of VRAM, system RAM available to your system was 3 GB). Win 7 and Vista said so (netted-out system RAM) but this isn't shown in Win 10 (don't remember if that was the case with Win 8/8.1). Is there a way to determine how much RAM is actually available to the system?

I just UG'd the BIOS of one of these PCs that was RAM-limited (now it supposedly may support up to 8 GB RAM on the MB - depending on MB revision) and was thinking of UGing (have to go with 2 x 4 GB as there are only 2 DIMM slots).

A quick search yesterday on the web didn't reveal an answer. I guess very few people ask about these limitations.
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Aug 22, 2006
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It's been a whole lot of years since I've used a 32bit OS (like XP was even 64bit for me) but I'm pretty sure you could tell from Task Manager how much available RAM there was after removing the VRAM.

A better question is why you're using 32bit. Every OS you listed has a 64bit version.
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32bit os limits to 4gb of memory address space, also chipset limits to certain maximum as well.
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death_hawk wrote: It's been a whole lot of years since I've used a 32bit OS (like XP was even 64bit for me) but I'm pretty sure you could tell from Task Manager how much available RAM there was after removing the VRAM.

A better question is why you're using 32bit. Every OS you listed has a 64bit version.
The limitation applied to 64 bit as well (which is what the condition under which the 2 systems were bumping up against the 4GB combined limit). It wasn't just the 32-bit (both systems came with VIsta x86 and were UG'd to Win 7 x64).
divx wrote: 32bit os limits to 4gb of memory address space, also chipset limits to certain maximum as well.
I do remember it was a chipset limitation. The one that may be less limited (Dell Vostro 220) should have an Intel G45 chipset while the one that seems to be more limited (HP Pavilion A1720n with Asus OEM MB) has an Intel 945G chipset.
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thriftshopper wrote: I do remember it was a chipset limitation.
Right... I forgot about that.
Still though, a 64bit OS with (let's say) 8GB+1GB should still show 7GB because I think the VRAM had to go in the first 4GB of address space that overlapped RAM.
The other 4GB should be available though.
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If you're using a dedicated video card with a 64-bit OS, video memory is separate from system memory. If you are using Onboard graphics, VRAM uses part of system memory.
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thriftshopper wrote: I just UG'd the BIOS of one of these PCs that was RAM-limited (now it supposedly may support up to 8 GB RAM on the MB - depending on MB revision) and was thinking of UGing (have to go with 2 x 4 GB as there are only 2 DIMM slots).
I guess your upgrade involve free or close to free used parts?

Not sure if that's worth the hassle other than personal gratification.
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On mainstream Windows, 32-bit editions, you'll only be able to use 3GB of system memory, even if you install more.

Easy solution is to install 64-bit Windows, which you'd only be prevented from doing if you had a really old PC like a P4 Northwood (S478) or earlier, or a Core Solo or Core Duo (not Core2Duo) and these two were really only found in laptops. Anything Prescott and later, C2D and later/better, will have 64-bit support.

For modern Windows (i.e. Windows 8.1 and later) you also need XD/NX bit support but again this is covered by the above; I believe there are actually some Prescotts that did not have this but the chances we're talking about a P4 here is probably very small.
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death_hawk wrote:
Right... I forgot about that.
Still though, a 64bit OS with (let's say) 8GB+1GB should still show 7GB because I think the VRAM had to go in the first 4GB of address space that overlapped RAM.
The other 4GB should be available though.[/quote]
Devhux wrote: If you're using a dedicated video card with a 64-bit OS, video memory is separate from system memory. If you are using Onboard graphics, VRAM uses part of system memory.
Board PCs had onboard graphics though they were switched off for discrete video cards. IIRC under Win 7 x64, the System Info (or whatever it was called) showed available RAM at 4GB minus either 512MB or 1 GB depending on which machine it was. Again, I think this was a chipset limitation.
Xtrema wrote:
I guess your upgrade involve free or close to free used parts?

Not sure if that's worth the hassle other than personal gratification.
The PCs were bought new. Just don't want to spend money on new PCs (unless I can get them really cheap - the main work desktop has been replaced by a Lenovo S30 obtained cheap). The RAM for the old PCs will be from ebay or wherever I can get them (really) cheap.

One PC (HP) serves at a music player and the other (Dell) serves as a HTPC (will require an UG for the video card (1030?) when I get a 4K TV). I did acquire an AMD tri-core Phenom which could do with the 2x2GB RAM that the Vostro currently has. That may replace the HP as the music server.
ES_Revenge wrote: On mainstream Windows, 32-bit editions, you'll only be able to use 3GB of system memory, even if you install more.

Easy solution is to install 64-bit Windows, which you'd only be prevented from doing if you had a really old PC like a P4 Northwood (S478) or earlier, or a Core Solo or Core Duo (not Core2Duo) and these two were really only found in laptops. Anything Prescott and later, C2D and later/better, will have 64-bit support.
The machines are both Core2Duos but Win 7 x64 showed the above 4GB minus discrete video RAM. This "feature" was removed in subsequent versions (Win 8 IIRC). These machines are from ~2007-08 so may have chipsets that limited the amount of RAM. The Dell Vostro is supposed to be able to support 8GB now with the BIOS UG but I dont have 2 x 4GB DDR2 to test it out.
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if you want to add a little bit more life the system, buy a used $7 xeon cpu and swap it over.
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thriftshopper wrote: Is there a way to determine how much RAM is actually available to the system?
Yep, at post, you'll see how much RAM BIOS thinks you have; no matter what you do, you will never see more than that at the OS. Otherwise, you can run Task Manager, click the "Performance" tab, then select "Memory" on the left (or just look at it; mine currently says 11.4/15.9GB (72%), and I have 16GB of RAM). For more details, click the "Resource Monitor" link in the "Performance" tab, inside Resource Monitor click "Memory", and you'll get an image of what is being used (I don't have RAM assigned to onboard video, so I am not sure how it would look ... probably grey for "Hardware Reserved").

Your statement about Vista/7/8/Win 10 is not accurate I don't believe; it is only accurate for 32bit versions of those OSes. I know I was running XP x64 at my workplace (disaster) with 8GB of RAM, and the software we were using was using all of that RAM.

That's a pretty old system to only have supported 4GB of RAM bone stock; my motherboard from 13 years ago supported 8GB. I doubt 8GB of RAM will sort out any performance issues you're experiencing with that system.
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ChubChub wrote: Yep, at post, you'll see how much RAM BIOS thinks you have; no matter what you do, you will never see more than that at the OS. Otherwise, you can run Task Manager, click the "Performance" tab, then select "Memory" on the left (or just look at it; mine currently says 11.4/15.9GB (72%), and I have 16GB of RAM). For more details, click the "Resource Monitor" link in the "Performance" tab, inside Resource Monitor click "Memory", and you'll get an image of what is being used (I don't have RAM assigned to onboard video, so I am not sure how it would look ... probably grey for "Hardware Reserved").
It counts up to 4096MB on both but I doubt they're all accessible (see below).
Your statement about Vista/7/8/Win 10 is not accurate I don't believe; it is only accurate for 32bit versions of those OSes. I know I was running XP x64 at my workplace (disaster) with 8GB of RAM, and the software we were using was using all of that RAM.
I went cheap-ish with a pre-built and got what I paid for (or less). As DvX said above, the Intel 945 chip set apparently has a maximum addressable RAM of 4GB, irrespective of OS.
https://www.intel.com/Assets/PDF/datasheet/307502.pdf

The G45 chipset (in the Dell) will support 8GB but Dell crippled the (Award) BIOS so that it only would use a max of 4 GB. The last BIOS update released (which I had downloaded but never installed) apparently allows 8GB on certain systems. I need 2x4GB of DDR2 to test it out however.
That's a pretty old system to only have supported 4GB of RAM bone stock; my motherboard from 13 years ago supported 8GB. I doubt 8GB of RAM will sort out any performance issues you're experiencing with that system.
Or cheap and nasty (the HP came with 1 GB RAM) - see above. Don't have any performance issues with what I use it for other than lag and slowness due to a lot of disk thrashing with Winchester drives (I should just get some SSDs for the OS and apps, but waiting for the price to go down). An SSD in the HP speeded it up a lot, but I took it out for the S30.
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thriftshopper wrote: It counts up to 4096MB on both but I doubt they're all accessible (see below).

I went cheap-ish with a pre-built and got what I paid for (or less). As DvX said above, the Intel 945 chip set apparently has a maximum addressable RAM of 4GB, irrespective of OS.
https://www.intel.com/Assets/PDF/datasheet/307502.pdf

The G45 chipset (in the Dell) will support 8GB but Dell crippled the (Award) BIOS so that it only would use a max of 4 GB. The last BIOS update released (which I had downloaded but never installed) apparently allows 8GB on certain systems. I need 2x4GB of DDR2 to test it out however.

Or cheap and nasty (the HP came with 1 GB RAM) - see above. Don't have any performance issues with what I use it for other than lag and slowness due to a lot of disk thrashing with Winchester drives (I should just get some SSDs for the OS and apps, but waiting for the price to go down). An SSD in the HP speeded it up a lot, but I took it out for the S30.
Sorry, I thought you'd said BIOS was updated to support 8GB. Lots of chipsets had 4GB limitations, but if BIOS had an 8GB update, that means the chipset must have been able to support it. Maybe it's a situation where you could have had one of two chipsets in that machine, and one of them supported 8GB? Regardless of that, an SSD will gain you WAY more performance than going from 4GB to 8GB of RAM would. No need to go wild on the SSD either; any old SSD is lightyears ahead of those old spindle drives. Also, I haven't heard someone refer to spindle drives as Winchester drives in at LEAST 25 years; thanks for that!

As for "I doubt they're all accessible": pretty easy test ... turn off the swap file, keep loading stuff until you're past 3.25GB. If your PC doesn't crash, it can address that space. Also, in BIOS, I presume there is a setting to define how much VRAM is available to the onboard. You said it's 1GB, but it seems way more likely it's something like 32 to 64MB.
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