x86_64 + AGP -> IOMMU == poor or enough?

[ZicoTheTux]

Hi guys

Recently I read some things about IOMMU support for x86_64 systems. I always use a recompiled kernel with agpgart modules which is only available if IOMMU is disabled. I need it because I stil use an AGP card (6800 Ultra)

Is that the only way to get it working? I know there is the way to use NVIDIA's internal agp interface but will I loose performance? I have no problems in recompiling my kernel but it would be nice as well to have a default kernel I just need to upgrade in a binary way.

So what would you say?
Using the modified kernel with agpgat or with IOMMU and.... which settings? How is your performance then?

Thanks for the answers.