Radeon HD 2600 series has a fighting chance to beat the
Geforce 8600 series. ATI did delay its 65 nanometre parts but fortunately at
least they are going to perform good.
The A12 samples worked at 800 MHz core and there are some indications that the final A14 silicon might be even faster. There is an indication that Radeon 2600 XT should be able to beat Geforce 8600 GTS including the overclocked ones.
The good news for ATI is that its core is made in 65 nanometre production process and won't have big heat dissipation and will easily outrun Nvidia clock by clock. We are still not sure if ATI RV630 will beat Nvidia in every benchmark but we heard that it can beat it in at least a few popular games.
Give it some time.