Re: AMD dual core vs Intel core 2 quad
On Wed, Feb 06, 2008 at 08:35:44AM -0800, Francesco Pietra wrote:
> In the last few days I asked advice about upgrading from a 2-way Tyan
> motherboard Thunder K8WES2895 with two series-2xx AMD dual core opteron to a
> 4-way motherboard. I learned from both Lennart Sorensen and Daniel Tryba that I
> can't use my series 2xx and should buy series 8xx. The price for such system is
> largely beyond what I can afford for private use.
>
> I am wondering about abandoning totally my present system of dual opteron,
> saving the disks, power supply, and, most important, the 24 GB of Kingston
> KRV400D4R3A (184 pin) memories.
>
> Abandoning to change to Intel Core 2 Quad Q6600 or 6800. The price is
> attractive and the choice of motherboard is wider, possibly up to a 8-way
> system (hopefully the 184-pon slots can be used). How does such Intel core 2
> compare with dual core opteron in terms of number of independent cpus? To be
> specific: when I run molecular dynamics (MD) on Debian amd64 with my shared
> memory Thunder with 2 AMD dual core, parallelization support OpenMPI
> (everything compiled with Intel ifort/icc), the MD program sees 4 cpus and "top
> -i" indicates four cpu at work. The gain with respect to running MD in serial
> mode is about threefold, i.e. the parallelization is not bad at all. What can I
> expect - from this viewpoint - with four Intel Core 2 quad?
>
> (Compilation of the Forthran MD program with Intel gives a tremendous burst
> with respect to GNU Fortran compilers)
The Core 2 Quad (like the Q6600) is for single socket systems only. You
do multi socket with intel you must use Xeon processors, which on many
boards require FB-DIMMs for memory.
The Core 2 Quad also being a desktop cpu does not support registered
memory, which is what many servers (like the opteron) uses.
So your current RAM will not work with a desktop system, and probably
wouldn't work with most Xeon systems. Xeon systems need fully buffered
memory to support having large numbers of DIMMs on one memory
controller, since they only have one, while the opteron has one per CPU
and can hence reduce the number of DIMMs per memory controller while
still allowing a large amount of ram.
As for Core 2 Quads, the Q6600 is nice for the price, and the Q6700
isn't bad either. The new low power chips (45nm) look even better like
the Q9450 and Q9550. The QX9650 and QX9770 are rather expensive.
--
Len Sorensen
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