I have a celeron 2.4, 1G RAM and a GeForce 6500/256.

Is that a fast enough machine to run GTRx?

It may run, but it will be pretty borderline. I just upped my system to 2GB, and a GEFORCE 7800 video card and it runs i decent now.....it still slows down a bit in traffic.

Well, I used some of my bonus to upgrade the PC.

Asus MB
Quad Duo 2.8
4GB
8800GTS 512M
Logitach G25

blah, blah, blah

And have been running GT Legends.

It certainly doesn't have the same feel as the real thing.
But it is helping me smooth out my technique, experiment with chassis tuning scenarios and fine tune coordination.

It was a chunk of change and switching PCs is a royal PITA. I hope it will pay dividends.

When I have time to kill in the winter a few beers and sitting down with GT4 on a track doing time trials chasing my ghost replay does seem to help. What I try and do is find time each lap and that is one hell of a way to do it. It teaches you line and where time is and is not in a lap. People can say that it doesn't help and it's not realistic but there are a lot of young F1 and Cup drivers that use it to learn tracks and lines. It's not going to get you turning your head, looking in the right spots and getting your inner ear canal a work out but it will get you thinking better, evaluating tracks for where you leave time out there AND it's got to help hand eye.

Funny story, back in college I would have GT2 on the Playstation at a party and some new kid would come over and want to race. My buddies would offer up a pitcher of beer at the bar for a bet and I would sweeten the deal with a slow car or a lap lead, something way out to lunch just to get the kid to race. Then just put a beating down on him, my buddies loved it since they knew it was about a sure things as bets go!

Bret