Just a me too:
I also have the Xid freeze with an old tnt2 model64/64pro.
I can trigger it systematically with mozilla when browsing kernel.org
and clicking on a link there. I guess Linus really doesn't like when
his kernel is tainted
RenderAccell doesn't make a difference.
Setting NoRenderExtension makes the freeze disapear but my icons
and fonts look terrible.