That's some serious crunching power!
How does 1 of those 8 core CPU's compare to 2 modern quad machines? (cost & performance).
well that would depend on the general quad core design you use for comparison:
AMD Phenom II (Deneb) vs AMD FX series (Zambezi & Vishera) vs A6/A8 series (Llano & Trinity) quad cores vs Intel Core i5 23xx/24xx/25xx/33xx/34xx/35xx series quad-cores (Sandy Bridge/Ivy Bridge) vs Intel Core i7 26xx/27xx/37xx/38xx series quad-cores series quad-cores (Sandy Bridge/Sandy Bridge-E/Ivy Bridge)
obviously the 8-core Opteron 6128 is now discontinued, but according to camelegg, newegg's highest and lowest prices were $310 and $250 respectively. assuming you can get a used one in good condition for ~$200, you would also need a socket-G34 mobo. while single-socket G34 boards aren't nearly as expensive as dual or quad-socket G34 boards, they aren't inexpensive either...the cheapest one on newegg goes for $225. now the board will take both ECC and non-ECC memory, but i don't know whether or not the Opteron 6128 requires ECC memory...let's assume regular non-ECC memory will work, allowing us to take memory out of the equation and focus just on CPU and mobo costs. so that puts us at ~$425 for the 8-core Opteron 6128 CPU and a single-socket G34 mobo.
1) AMD Phenom II X4: a used 965 BE will be in the neighborhood of ~$100. you could get an AM3 board on the cheap (~$50), or you could get an AM3+ board for future upgradability (~$100)...either way, you're probably looking at $200 at the most for a Phenom II X4 CPU and AM3/AM3+ mobo.
2) AMD FX series quad-core: there doesn't seem to be much of a price delta between the older Zambezi (Bulldozer) quads and the newer Vishera (Piledriver) quads right now (~$110-$130), so with an AM3+ mobo (~$100), you're in there right around $230 tops.
3) AMD A6/A8 series quad-core: the A8-3870K is the most expensive A6/A8 quad-core CPU on newegg right now @ $105. the most expensive socket-FM1 mobo on newegg right now is $115 (before rebate), so on this platform you'd come in around ~$220.
4) Intel Core i5 quad-core: these CPUs seem to be in the $190-$220 range brand new. now i'm not real familiar w/ all the differences between Intel's current chipsets (Bxx vs Hxx vs Pxx vs Qxx vs Zxx), but i see some selling for as little as $50, and some selling for as much as $450...so this platform could run you anywhere from $240 to $670.
5) Intel Core i7 quad-core: these CPUs seem to be in the $300-$330 range brand new. with the same lot of mobos to choose from, this platform could run you anywhere from $350 to $780.
so from a "CPU-&-mobo" only perspective, only the slightly aged Phenom II platform can be purchased twice for significantly less than a single Opteron 6128 platform. if you are building from scratch and don't already have the other necessary hardware on hand, then even the Phenom II platform starts to look a bit long in the tooth b/c you'll have to buy 2 of everything else (case, PSU, memory, CPU cooler, possibly GPU, etc.).
now from a performance point of view, i would imagine that 2 of any of the above platforms (save for the Core i7 CPUs) would be pretty comparable in performance to a single Opteron 6128 platform, but would consume a good deal more power in the process. i would imagine that only the Core i& CPUs would compare favorably w/ respect to both performance and power consumption due to HyperThreading - these quad-cores have 8 threads (4 real cores and 4 virtual cores). the i7's are typically clocked much faster than the 6128, and probably have more efficient instruction pipelines, but the 6128 has the advantage of 8 real cores. at the end of the day, its probably a wash between a single Opteron 6128 platform and a single Core i7 platform. obviously 2 i7 platforms equals 16 threads, and will outperform a single Opteron 6128, but it will also consume a good deal more power.
