Benchmarks: Ultra - HBAO+ Disabled
Disabling HBAO+ earned up to a 10fps performance increase at 1680x1050, with the GTX 670 being 9% faster, 12% for the HD 7950 Boost and 18% on the HD 7970 GHz Edition. HBAO+ is a new Ambient Occlusion technology designed by Nvidia, so it's no surprise that the technology favors GeForce cards.
As a result, playing without HBAO+ gave AMD cards a massive performance bump, so much so that the HD 7970 GHz Edition came within 1fps of the GTX Titan. This boost also helped the mid-range cards as the HD 7970 Boost was just 1fps slower than the GTX 670, rather than 4fps.
The increase also let cards such as the GTX 660 and HD 7870 break 60fps, while low-end cards such as the HD 7770 and GTX 650 Ti only saw minor gains when disabling HBAO+. That said, although the HD 7770 only went from 30fps to just 33fps, that's still 10% better.
Increasing the resolution to 1920x1200 forced the HD 7970 GHz Edition behind the GTX Titan, though it was still 2fps faster than the GTX 780. The HD 7950 Boost was 1fps slower than the GTX 670 while the GTX 660 Ti delivered a healthy 66fps.
With 57 and 56fps respectively, the GTX 660 and HD 7870 both offered excellent results for their price.
Cranking the resolution to 2560x1600 saw the HD 7970 GHz Edition fall well behind the GTX Titan (as it should) with an average of 59fps, though it was still 1fps faster than the GTX 680 and just 3fps slower than the GTX 770. On AMD's side, the HD 7950 Boost managed to meet the GTX 670 at 51fps.