This is something that I’ve been curious about for some time now but just never stopped to ask anyone. The comparison between Linux and Windows game performance has been an issue for some time now. I have read of the improvements in the performance of Ati and Nvidia drivers, but what about the motherboard agp and more recently Pcie drivers?
My mobo uses a Via chipset and although I have a working 8x agp there are no drivers for it from Via for Linux. I suspect many if not most people are in the same position, but nobody ever seems to mention this. I wonder if I would get better 3d game performance with a mature driver from Via than I do with the the driver that came in openSUSE.
How your mainboard interacts with the OS is more to do with BIOS. Updates to BIOS can sometimes resolve hardware issues in either OS you mention. 3D performance in Linux is just fine, and I assume you have successfully installed your Nvidia or ATI driver. There are a plethora of comparison tables for graphics card performance in windows - but to be honest most Linux users are not too concerned - but if they are - tweaking is possible as it is in windows.
It is seldom necessary to compile drivers for mobo chipsets, though they are available. If I go Asus - I can download drivers for my mobo but it works just fine as it is.
I hear what you are saying - but there can be only a handful of situations where we could make a comparison between Linux and windows game performance - and even then, it’s not really going to be like for like.
The Via and SiS chipsets are known to have weaker support than Intel, ATI, and NVIDIA graphics vendors. Thankfully, the latter 3 are in wider use anyway.
Via petition for linux drivers:
DECENT VIA GRAPHICS DRIVERS FOR LINUX Petition
Via support forum:
VIA Linux - Phoronix Forums