[OT] Re: Suggestions for a good graphics card for RH9/Fedora?

[Mike A. Harris]

On Thu, 23 Oct 2003, Xose Vazquez Perez wrote:

>I saw tests of same ATI board with 64 and 128 over MS Windows and they get
>the *same* performance. Forget the RAM, it's more important chip type.
>A Radeon 8500 or 9100 with 64 MB is good and cheap.

The amount of video memory on a board doesn't indicate the 
performance one will see out of it.  The only time the amount of 
video memory affects performance at all, is when the software you 
are using has a LOT of textures, and the textures do not fit into 
video memory anymore.  When textures don't fit into video memory, 
then AGP textures must be used which are slower.  If you run a 
high end modern game like UT2003, you will definitely see a very 
big difference between a 64Mb and a 128Mb card, with both clocked 
identically with same speed and same type of memory, because the 
game will fill video memory on both cards easily.

Also, depending on how much system RAM one has, if you run games 
which require a lot of texture memory and you only have 64Mb of 
video memory, the memory gets used via the agp aperture, and that 
is system memory stolen for the purpose of texture storage.  If 
you only have 128Mb of system memory, and a 64Mb GART size, that 
means your system only has 64Mb of useable memory for 
applications.

If you run glxgears to benchmark hardware, you'll see the same 
performance on a 256Mb card as a 64Mb or 32Mb, or even an 8Mb 
one, as glxgears doesn't have 256Mb of textures to stuff into 
video memory.

Hope this helps.


-- 
Mike A. Harris     ftp://people.redhat.com/mharris
OS Systems Engineer - XFree86 maintainer - Red Hat