1) i guess you could check benchmark comparisons, loads of sites have them, like xbitlabs and anandtech. cpus do so much and their architecture have advantages and disadvantages, so like...there wouldn't be one measurement of saying, for example, that cpu A is better at gaming but worse at divx encoding compared to cpu B (which I think was the case with amd and intel not so long ago?).
also, those articles give you a lot more information, like how quiet, how cool, overclockability, features, etc., so it's really the best way to know what you're buying. but...if you really don't have time, then i guess the one measure of how good a product is, though DAMN unreliable, is price.
2) scsi drivers are louder i think, too. other than that, most have been mentioned, better speeds, for servers, etc.
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PC Specs:
Gigabyte GA-965P-DQ6 1.0 F11 | Intel Core 2 Duo E6600 2.4GHz @ 3.4GHz | 2x Maxtor 250GB SATA II HDD RAID0 |
2x Corsair TWIN2X1024A-6400 DDR2 800 (512MX2) | Gigabyte GeForce 8800GTS 320MB | Tuniq Tower 120 |
Dual Boot: Windows Vista x64 & Windows XP Pro SP2