Can bandwidth offset VRAM capacity?

[Carfax83]

If a card is lacking enough VRAM, to what degree can bandwidth mitigate that limitation?

I'm constantly surprised at the ability of my GTX 580s to handle the latest games at very high or ultra settings. I would figure that having 1.5GB of VRAM would limit their ability to play these games, but it hasn't stopped me.

Take Crysis 3, the best looking PC game ever.. I can play Crysis 3 @ 2560x1440 everything on very high, SMAAx1 and V-sync turned off and get 35 to 40 FPS for the most part; very playable indeed.

Anyway, back to bandwidth. My GTX 580s are overclocked to 900 on the core and 4400 on the memory. At 4400, my memory bandwidth is 211 GB/s according to NVidia inspector.

So does that offset the relatively low amount of VRAM I have?

 

[alcoholbob]

Why SLI 580s is no slouch, isn't that basically as fast as a Titan? And VRAM is usually not an issue unless you go triple screen or massive AA.

 

[Carfax83]

Why SLI 580s is no slouch, isn't that basically as fast as a Titan? And VRAM is usually not an issue unless you go triple screen or massive AA.

No they're no slouches to be sure, but having 1.5GB of VRAM seems rather low by today's standards and I would have thought it would cripple the performance of the GPUs..

 

[BallaTheFeared]

No, bandwidth won't make up for a lack of vram. If you don't have enough vram than you're reduced to the speed of your drive and system ram as that is where the textures will be stored and streamed from.

First sign you don't have enough vram is stutters as textures are pulled off the slower components listed earlier. After you've gone well past your buffer limit you start seeing performance tank completely, 3-8 fps avg type tank - the game won't even be playable.

It's not as simple as "I'm using 1.5GB according to AB", games will also load textures it doesn't need.

1.5GB isn't ideal, but reducing resolution, lowering texture quality, and even using FXAA/SMAA over MSAA are all good ways to stretch the life of your cards.

 

[Jaydip]

If a card is lacking enough VRAM, to what degree can bandwidth mitigate that limitation?

I'm constantly surprised at the ability of my GTX 580s to handle the latest games at very high or ultra settings. I would figure that having 1.5GB of VRAM would limit their ability to play these games, but it hasn't stopped me.

Take Crysis 3, the best looking PC game ever.. I can play Crysis 3 @ 2560x1440 everything on very high, SMAAx1 and V-sync turned off and get 35 to 40 FPS for the most part; very playable indeed.

Anyway, back to bandwidth. My GTX 580s are overclocked to 900 on the core and 4400 on the memory. At 4400, my memory bandwidth is 211 GB/s according to NVidia inspector.

So does that offset the relatively low amount of VRAM I have?

If you are Vram limited more bandwidth won't help you.

 

[Carfax83]

No, bandwidth won't make up for a lack of vram. If you don't have enough vram than you're reduced to the speed of your drive and system ram as that is where the textures will be stored and streamed from.

So how does high bandwidth help GPU performance exactly?

Also, I never asked whether bandwidth would make up for lack of VRAM, but whether it could mitigate it somewhat..

First sign you don't have enough vram is stutters as textures are pulled off the slower components listed earlier. After you've gone well past your buffer limit you start seeing performance tank completely, 3-8 fps avg type tank - the game won't even be playable.

Never encountered this before, so I guess I'm good.

1.5GB isn't ideal, but reducing resolution, lowering texture quality, and even using FXAA/SMAA over MSAA are all good ways to stretch the life of your cards.

Yeah, I try to use FXAA/SMAA as often as possible. Although I hated FXAA when it was first introduced due to the blurriness it caused, it seems that it has been much improved.

Far Cry 3 with post fx on ultra uses FXAA, and I can detect no blur at all. Mass Effect 3 is the same..

 

[Enigmoid]

I think (but aren't quite sure) that bandwidth can help with vram. In the consoles (specifically looking at uncharted in ps3) I think the game was designed to flush assets out of vram that were no longer needed and then replace them again when they were required. But it seems the game must specifically be designed for this.