Agreed. 64bit makes a big difference with most drivers. A shelled OS helps too. I run xp64 shelled to hyperspin.
I don't recall trying TC2 but I can tell you none of the ridge racers drop a frame on my i5 2500k @ 4.3ghz (stock air).
Gradius 4 still skips but only a bit. About 95%. Same with GTI Club. Sandy Bridge was a huge step up from C2D, especially the unlocked CPUs. Think we will be waiting a bit longer than Haswell for the next real speed bump though.