These posts are misleading. Please let me clarify things out, 6600GT is low end and expect to play the most intensive current and near future games at 800*600 low to med or 10X7 low settings. I too had one with a 3200 64bit AMD and 1GB dual ch RAM.
Hitman Blood Money, I didn't play on it,but I can estimate that it will run fine albeit at 10X7 low to med at the max.
Oblivion will be 800*600 low to med and GRAW maybe even worse.
Please don't be misleaded.
Also, 2.47GHz is not enough, in fact it is very little for todays games.
2.8HT is a bottleneck unless you overclock it to 3.2-3.4GHz atleast, 2.8 has become the bottleneck speed, after overclocking it will become better.