New Hard Disk

I went out yesterday and bought a new hard drive and now have everything installed again. It certainly feels a lot faster. I'm trying to figure out why and here is what I have come up with:

1. I installed all the latest drivers from Dell with improvements
2. The hard disk is faster (5400 instead of 4200 RPM)
3. I don't have a lot of extra programs installed yet
4. All the files have just been written to disk so they aren't fragmented yet
5. The hamsters inside my computer are running faster

Whatever the reason, I'm really enjoying the new speed. There was a time a few months ago where this laptop was so slow it was barely useable.