Real RAID card will *not* increase the performance of his system more than buying a Raptor would. Real RAID card may increase the theoretical performance of his RAID array, but in real world terms the lower rotational latency of a 10k drive will result in a substantially faster computer.
Personal computer's drive access pattern is almost entirely non-sequential reads and writes.
10k drive is much better than 7.2k drive for non-sequential reads and writes.
How much $ do you have to spend?
1) The whole series of Athlonx2's are cheaper than dirt now, so that'd be your cheapest upgrade
2) Then again, why spend money to go back in technology? You can get an E6300 for $187...Overclock it, and have it perform better than an AMD-FX 64 so...Why pay for worse technology? The only drawback is buying a new mobo...but like I said if you've got money then why not?
3) As far as Raptors go, I don't recommend you get one just for gaming. I don't find that my game load times are really much quicker...the only thing that IS a little quicker is maploads on BF2. Other than that, it doesn't help gaming hardly. It really shines on rendering tasks like encoding, a/v rendering and editing, disk defrags, etc. But it def. won't increase fps, and I don't think its worth the money for loading a game map a bit faster. If I hadn't gotten it for my bday, I def. wouldn't have spent my own cash on it.
I'm sure there will be those who take issue with what I'm saying, but I disagree that a dual core CPU will fix the bottle neck. It's always important to look at what a person is using his computer for, and for gaming, dual core makes little difference as games are still single-threaded. In fact, a 4200 X2 running at stock 2.0 Ghz per core will run SLOWER in games than what he currently has since the game will only utilize 2.0 Ghz. That being said, if like me he likes to multi-task while gaming, then by all means get the dual core. For pure gaming performance, however, I recommend getting a raptor for your OS and game installations. I did, and I'm very happy with the boost it gave.