[stephengillie]

Actually, the performance difference is small. The biggest gain we have today is multi-cores, so no one thread can hog all processing pipelines. If you're pushing through 1 billion instructions, it will still take 1/3 of a second for your CPU to chunk through all of it, but other code can be processed simultaneously on another core.

I know, I know. My laptop (Lenovo T400) has almost the exact same specs as the old Sunfire V20 rackmounts I have (2x2.4ghz cores, 4gb ram, passable video), but the laptop can run on batteries for 5 hours.

But clockspeed is still king -- this T400 run circles around a Lenovo W520 with a 1.6ghz Core i7 and 3x the ram. I know because I had a W520 for work, and I could see the difference.