While trying to pickout the pieces for a new linux developers comp I got really confused. I just wanted a cheap computer. I wanted to build a computer myself once too, just to say I know how. So what the heck is the difference in the pins on the processor and motherboard, and why would I want l1, l2 cache along with sli, pci-e, and a bunch of other fancy acronyms. I couldnt find a good newby guide so I did a bit of research.
The main differences is: the SLI; which can run two video cards at once and increase performance, the 64 Bit mode; which makes things more efficient but most operating systems do not support it t o begin with(need XP Professional 64 bit edition), the cache; it makes things faster if your run memory intensive applications like databasing and datamining, and the speed 90nm from 130 isnt a killer difference, but it's noticable.
There are serveral things that affect your speed. The motherboard, the harddrive, the ram, the cooling, and the processor. If you're going to be playing the newest gaming releases on your computer you're going to want a 939 processor, but you have to buy a compatible motherboard/videocard/a good hardrive to get the best speed.
If you're just messing around with word processors and making small applications, then buy a sempron. They're cheaper, for the milliseconds difference it makes between the two doing standard operations.
I learned that a lot of gamers are paying 4times as much per gigabyte to buy a 150gig hard drive that runs at 10,000 rpm instead of 7200. I'm not sure how fast the front side bus bus has to be to not slow down the processor, or how fast the hard drive has to be combined with the processor to load something fast. Who knows. Buying the most expensive stuff is the best bet, as a lot of people seem to be doing. From 1.6 to 2 ghz isnt a massive difference unless your an obsessed gamer that's using computers for all the wrong reasons.
I ended up with a nice linux system at $300. 1.8ghz 512 ram, case, harddrive, fan, built in video/audio on the processor, built in power supply on the case. Super fast, and very cheap.