crossfire using more than 3gb memory?

[jcbiddulph]

Hi guys (first post)

 

Having a wierd reading on MSI Afterburner, Frame rates are far below what i expect and it is showing nearly 4gb of memory usage. I have 2 7970 3gb in crossfire and a triple monitor setup (running at 4800x900) how is it using more than 3gb? and how do i stop it? 

[SkulD]

Hi guys (first post)

 

Having a wierd reading on MSI Afterburner, Frame rates are far below what i expect and it is showing nearly 4gb of memory usage. I have 2 7970 3gb in crossfire and a triple monitor setup (running at 4800x900) how is it using more than 3gb? and how do i stop it? 

I monitored my 2 280x Vram usage with GPU-z, playing BF4 @2560x1080p, and I too saw a Vram usage of 4200Mb or so, MY guess is that it shows the combined Vram usage, so it will be  4200/2=2100Mb of Vram usage per card.

 

Again this is only my guess, I am no expert, and i hope someone comes and enligthen us .

[Raxzer]

It must be some kind of error or another interpretation of the memory usage.

 

In SLI and CFX, memory is mirrored. GPUs in a SLI/CFX-configuration operate in AFR, where the graphics processors alternate on rendering frames. This means that they'll both need access to the same information.

 

As far as I've seen, this is either an MSI Afterburner error or an CFX-limitation. Does other monitoring-programs give you the same result?

[jcbiddulph]

right i think I've found a different issue, when I'm in game (Assetto Corsa) with one car on track both GPU's are at 99% Usage (and showing 3.2gb memory usage) I get 120fps, but when I add lots of opponents the framerate plummets to 25fps and graphics cards are both only at 30% usage (but 4gb memory)