I recently built a few PCs for friends based on AMD’s Socket 939 architecture. Of course, shortly after the returns period ended on the last system I built, AMD discontinued the Socket 939 line. :smack: I’ve got to decide soon which prices to watch, and what constitutes a legitimate performance improvement, so I can grab the good 939s before they disappear off the shelves. The chips my friends are using are all “Athlon 64 3000+” and based on the Venice core. Their clock speed is 1.8GHz, but I know that with AMD systems GHz is not a great measure of performance (or has it become good again?). Anyway, the chips that would be suitable for upgrades are here.
All of the motherboards support 939-pin Opterons, Athlon X2, and the Athlon 64 FX series of chips, so pretty much anything is up for grabs. My gut feeling was to stick to these chips (dual cores w/ 2x1MB cache) on the grounds that you never want cache to be your bottleneck (because you need to get a new chip if you want more), and two cores ought to be better than one. However, I’m a little puzzled at (for example) the $265 price tag on the 1.8GHz Opteron. Why is it almost four times as expensive as the baseline chip we got? I understand that I’d be getting twice the clock speed in one package – that’s cool. The cache on each chip is twice as large as the cache on our current systems, and I can understand the difficulty in producing a chip with that much reliable memory on the die. Also cool.
I guess what I don’t really understand is the relative amounts of performance increase I’d be likely to see from:
- doubling my number of cores
- doubling my cache per core
- adding 50% to my current clock speed
I’m trying to find a good metric for overall performance so I can track price/performance ratios as the prices descend, and I fear that I just don’t understand how those three factors interact with each other. Help me Dopers - you’re my only hope!