Some hardware just won't overclock. If you bought really good RAM, then you should be okay. If you bought the ultra cheapo stuff, then you've got little sticks of death.
As for benchmarks, 3Dmark is great for gaming tests and I would definately suggest you figure out a way to get it to your PC. If you can't find a fast connection to download the demo to a thumb drive or something, send them an email and they'll mail you a copy on CD.