My computer is running near similar specs to yours and i can run rFactor, GTL and GTR2 on high graphics settings with decent enough fps. There are a few tracks out there that give me fps issues but luckily those tracks never get used here.
Race 07 was not as good for me as well. I had to run it on either med or low graphics settings to get decent fps and a lot of the tracks for R 07 didn't run well for me.
I also use Razor Gamebooster which shuts down some unnecessary background applications and it appears to work for me.
On your rFactor's desktop shortcut if you right click and go to Properties and add +fullproc +highprio to the target it helps a bit on the games performance. Well it did for me anyways.
Edit: And yes i'm one of the PST/PDT guys. Usually races start at 12:00pm for me but because now we're in PDT, races start at 1:00pm. I'm kinda lucky that i work evenings so when i'm not busy during the day i can join the gang for some racing.