Generally, ATI has historically provided better performance (espcially for 'pro apps') over similarly powered NVIDIA cards. Barefeats has recently shown so too. The results are somewhat puzzling, but true. Be it ATI, NVIDIA or even Intel, we can only hope fervently that cohesive collaborations between themselves and Apple --- such will bring about optimized performances for us, mac users.
p.s. Interestingly, the NVIDIA GeForce 8800GT indicates GDDR4 memory, which if it is to be believe, is certainly a very welcomed improvement over GDDR3. 'Pro apps' users will also appreciate if the 3870 comes in the x2 edition.
[update]
Apple Singapore has since updated the details.
