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AMD64 * 2 = waaaay expensive...
Date: 11/1/2005
I miss the dual CPU days so much I'm researching my options for getting into back into it again. My last dual system for a dual celeron 400, which was built to run BeOS. It was a sweet system for it's time, ran Windows 2k really well to boot. But time marched on and I got given an Althon 1.4ghz by my best bud. Which works fine, but it's only 1 CPU, and I'm doing a lot of video crunching these days, and it takes forever.

Now after my previous rant about the sad state of AMD64 dual motherboards and their prohibitive cost I've done some more reading and well, they need "Registererd" RAM don't they. For the uninitiated this "special" type of RAM has extra registers that buffer the bits in and out of the RAM chips, making sure they arrive safely. This allows the system to scale up to 16 sticks of RAM safely. However it does run slower.

Now AMD64 CPU's are frickin' cool. Lots of the stuff we love, new instruction set, more registers -> same code runs faster, better memory bandwidth etc etc. All good reasons to run AMD64, but the motherboards are like 50% more expensive that the equivilent Intel board and the Registered RAM is more expensive and slower. The chips themselves are same-ish in price, but I havn't been able to find any direct comparisions in speed of the AMD64 (socket 940 + 939) and Xeon CPU's at the various clock speeds I'm looking at.

Mind you all this is still cheaper than a dual G5: A$ 3,199.00. I priced out a dual Opteron 242 system at $2,642 and a single Althon 64 3500+ system at $1,825. Having to start from scratch with PCI-X cards doesn't help either and both systems are sans monitor or peripherals which I already have.
Comments:
fret
12/01/2005 12:50am
Found a cheaper way to do dual Opterons... (+ditching the LCD)








PartUnitsPrice
Opteron 2422$345.34
512MB ECC Registered PC32001$230.00
Tyan K8W S2875ANRF1$412.50
XpertVision GeForce 6600GT1$318.10
Case1$130.00
Total$1,781.28


I also found a slightly cheaper motherboard.
tozz
18/01/2005 11:09pm
I don't even think you can run Opterons with a single stick of RAM. Since each CPU has its own memory controller they need memory to control. For any use of the technology behind the opteron they should really have 2*512 each.
tozz
18/01/2005 11:16pm
btw, you mix AMD64 and Opteron around way to much. They're far from the same.

AMD64 doesn't need registered ram (the cpu is very latency dependent and registred modules slow CAS latency by one, way too much). The mainboards should come at around the same price as Intel ones, at least I've never seen the price difference you describe.

Opteron need registered ram. They are also running at one pin more than 939. Mainboards can come very expensive, but SMP isn't here to be cheap :)

Registered RAM isn't more expensive than GOOD Unregistered ones with low latency. (Needed for AMD64).

As I said in my previous rant waaay back the extra slowdown given by registered modules isn't enough to bring down the Opteron even close to AMD64 speeds, Opteron far exceeds it.
fret
18/01/2005 11:43pm
Yeah I know about the 2 sticks of ram, I was going to solve that later... either 2 x 256 or something...
fret
27/01/2005 6:21am
I think I can avoid the start from scratch with add-on cards by getting a dual opteron board that isn't PCI-X. It's cheaper as well.

I've got a dandy little collection of PCI cards now, and it would cost a fair chunk to replace them all. Mind you some of them come standard on motherboards these days anyway, like the 10/100 nic's and firewire ports.
 
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