What VRam actualy does?,

[Dethman]

The Question is, where does vram come into place?, Ive been looking at some comparison charts with some cards, and looking at the diffrence between the same card, exept one with 256 memory and 512 memory, And the charts place the cards very close, ussualy within a few FPS of eachother, This is at 1600x1200, (the resolution that I game at),

So im thinking then since the charts dont show much of a diffrence, its because the higher vram allows you to add more things like AA and AF and maybe HDR when your gaming at a higher resolution with less of a performance hit?, Is this correct? Thanks in advance.

 

[Rambo]

vram is faster for the card to access than system ram. the fps difference may not be much on some games, but be a huge difference on other games.

 

[Arcygenical]

Vram acts simply as a frame buffer. Lots of it allows for more complex textures, with less compression, more AA or AF, before you get memory starved.

But, the amount of Vram isn't the only limiting factor. Memory thoughtput, and bus width play a much larger roll at determining how much stuff can be enabled at one time.

 

[lunix]

VRAM is fast local storage for the GPU. The speed of the VRAM can help the GPU work faster by preventing the GPU from stalling while waiting for data to be loaded. The amount of VRAM helps prevent slowdowns in the event that it becomes exhausted.

VRAM stored all the vertex data, textures and the frame buffers. High resolutions use larger frame buffers and hence will use more VRAM. Games that use many high res textures for normal and specular maps will use lots of VRAM.

Once the VRAM is exausted the extra data gets swapped out over the bus to system RAM. Its like running windows on 128M of ram it starts swapping and you get slowdowns.

 

[ex0du5]

As long as you have enough VRAM, performance will be the same across all models. The advantage to more VRAM is when you want to increase texture size and resolution. If a game requires 400MB of VRAM to be loaded, you'll see a massive performance difference in between a 256MB card and a 512MB card. Most games only need lower than 256MB currently, but that can change pretty fast when you increase resolution.