Sorry it has taken so long to prepare a reply. I've recently gone thru the same exercise. You need to decide what you are comparing, in my case it was strictly processor speed. I've read with interest a number of processor reviews. A recent one is Sandy-E, which is fast! Link
Page 14 discusses the STARS Euler3d benchmark. It is a 14 MB zip file download. Running it helped me see how much faster my new processor is compared to what it replaced. Over 120% faster. It also helped me see which of two other Core 2 Duo PCs was faster. This appears obvious from the model numbers (4300 vs 6300). However the 6300 was only 5% faster when I loaded both cores for 20 passes of the benchmark.
My build thread: Link
I started to look at which is faster; running the benchmark on the new processor with hyperthreading vs without. The benchmark numbers say no hyperthreading is faster by approx 7%. Not extensive testing. The system monitor "looks" better with hyperthreading enabled.