Video ram larger than system ram

[sead123]

Can 2GB video card works with 1GB system ram?
Or 4GB video card on 2GB system ram.

 

[Yuriman]

It works, and it is, but it's probably not a good idea. What parts are we talking about here?

At one point I had a 64MB Geforce2 paired with a Pentium 1 with 64MB of total system RAM.

 

[Beavermatic]

As yuriman said, you can have more vid ram than system ram, and vice versa.

It'll run, but of course, with system RAM that low id assume your not playing games (or very intensive ones), any card that has 2GB's of VRAM will likely be serious overkill in both VRAM and performance required.

Then again, most cards, even entry level, come standard with 2GB's of VRAM anymore, so hmmm, maybe its plenty fine.

Though if your buying higher end vid cards, say... a GTX 770 or 780 (or even 670 or 680), and expect to do some highend gaming (which those cards are capable of)... that 1GB of system RAM wont cut it for any games requiring such graphical power and vram, and VRAM does not add total amount of RAM to your system, as they are used for separate purposes in games.

Basically your video cards would be sitting there, twiddling its thumbs, waiting for the rest of the system to keep up.

 

[BrightCandle]

Yes it works and the reason is that the VRAM is not mapped and copied into RAM. Instead what happens is the GPU maps what is known as a port into the memory space that allows it to only transfer a relatively small amount of memory but with instructions on where. When I check my GPU it takes up the following memory ranges (device manager):

FA000000 - FAFFFFFF = 2^24 = 16777216

C0000000 - C7FFFFFF = 2^27 = 134217728

C8000000 - C9FFFFFF = 2^25 = 33554432

A00000 - BFFFF = 2^17 = 131072

Total = 184680448 bytes = 176.125 MB

So just 176MB of mapped address space. That isn't RAM used however its just memory space used for mapping the 2GB of VRAM of the card and sending commands to it.

However according to PNY a 2GB 680 GTX requires 2GB of system RAM, presumably for the drivers and such. But there is no special relationship to the amount of VRAM available on the card, just the resources necessary to play a game and use said card. Its VRAM is not in any way mapped directly to the RAM of the PC.