Those who r using windows 7, how is the beta version running. does the beta have any problem?

Windows 7 is definitely much smoother than Vista. I'm not sure I would say it's 70% faster, but it does simply feel like it "hiccups" less. You should definitely wait for Windows 7; do not buy Vista now. In fact, a public releases candidate will be available, without download limitation tomorrow. My configuration is very similar to yours (same processor, Intel mobo, 4GB RAM).