What happens when you run out of VRAM?

[Guest]

My computer is running a GTX 590 and an i7 2600k at 4.6 ghz.

Now I know that the 590 has 1.5 gb of usable VRAM, even though the box claims it has 3gb (1.5 gb per GPU) and people are saying that that's quite low for today's gaming standards.

So, I want to know how to recognize if a game I'm playing is trying to use more VRAM than my video card can provide. So far, the lowest my FPS has ever dropped in Battlefield 3 is 50FPS - I'm not sure if this is because I run out of VRAM?

When I try to use more VRAM than my card will provide, will the game crash? Or will the frame rate drop to something extremely low like 10-15, or will it only drop a little bit like to 50-ish?

Thanks for the help guys.

 

[InvalidError]

Modern GPUs will run into a hybrid mode where the drivers/GPU start streaming texture data from system RAM over the PCIe bus to make up for the "missing" RAM. Since system RAM is 3-5X slower than GDDR5 with much higher latency, running out of "VRAM" would translate into a significant FPS loss.

In most games though, you are not likely to run out of GPU RAM unless you run with a high level of FSAA or other memory-hungry feature.

 

[Guest]

Modern GPUs will run into a hybrid mode where the drivers/GPU start streaming texture data from system RAM over the PCIe bus to make up for the "missing" RAM. Since system RAM is 3-5X slower than GDDR5 with much higher latency, running out of "VRAM" would translate into a significant FPS loss.

In most games though, you are not likely to run out of GPU RAM unless you run with a high level of FSAA or other memory-hungry feature.

Oh.. So running out of VRAM would cause a huge FPS drop.

So you're saying that what I'm experiencing in BF3 (a drop to 50 fps) is not because I'm running out of VRAM?

How low do you think the FPS would drop if I were to run out of VRAM?

 

[InvalidError]

How low do you think the FPS would drop if I were to run out of VRAM?

Depends on how much texture streaming is happening. If textures streamed from system RAM account for only a small percentage of total rendering, the slowdown may be barely measurable. If large chunks are pulled from system RAM, it can turn into a slideshow.

 

[edogawa]

When and if you happen run out of video memory, then your PC will have to constantly jerk textures between main memory and video memory, which causes massive slowdowns, generally to unplayable levels.

I would not worry about that at all as long as you have a 1GB of VRAM on a single monitor; this may change in the future though as technology advances.

To sum it up, don't even bother worrying about VRAM, unless you run multiple monitors at high resolutions.

 

[Sakkura]

1.5 GB VRAM is fine for 1920x1080 / 1920x1200, it's only with higher resolutions (and lots of AA) it would be a real problem.

 

[esrever]

When you are at the limit for vram, you will notice. The game will be really laggy, 20-30 fps at the most.

You will have a slight fps loss when you are close to and the needed vram but it won't be significant enough to matter. The VRam is continously being written to and read and deleted, much of the used vram people read off software isn't even needed. 1.5 gb is plenty.

 

[Guest]

Best answer selected by DTsoy.

 

[Guest]

Thanks guys.