Nouveau Performance Is Faster With Linux 3.12
With OpenArena 0.8.8, which was one of the common AMD test cases where the performance was up under the Linux 3.12 kernel due to the CPUfreq ondemand governor change, this was also the case for Nouveau. The NVIDIA GeForce 9800GTX that was running at 675/1100MHz via re-clocking was 25% faster when upgrading from Linux 3.11 to Linux 3.12 Git. The GeForce GT 220 that was re-clocked to 625/405MHz didn't see much of an impact by the Linux 3.12 kernel upgrade since it's a low-end part and wasn't being starved by the frequent low clock-speed and ping-ponging on Linux 3.11 due to the faulty ondemand governor. While the NVIDIA GeForce GTX 600 series can't yet re-clock with Nouveau, the GTX 680 saw a 40% performance boost when upgrading to the Linux 3.12 development kernel.
There were similar but lessened gains when running OpenArena at a higher resolution of 1920 x 1080: the 9800GTX was 13% faster and the GTX 680 was 4.5%.