Hi,
Its actually an i865 and "must remain" an i865. Its amazing, the 3D performance (with shadows and all) is pretty fast if I disable the code that results in the screen blits.
I have never used an Intel chip, so I can't judge about it's speed.
If you'd like, I'd be willing to help out if I can on getting this working better. Sounds like you've gotten a head start on it.
I'm quite busy now with finishing my ddraw patch, but when that is in and the regressions are out, I'll ask for apps that aren't working as they should, and then I can look at it. Except, if you desperatly need this blits working, I can have a quick look at it.