cjl said:

Well, I use my i7 for MATLAB all the time, and it is less well threaded than you might think. On pure, large matrix operations, it is extremely well threaded. However, on almost any other task, it seems to be more governed by single thread speed and memory speed than anything else. Because of that, I'd recommend an i7 as the first choice, and a Phenom II as a second choice. Both have integrated memory controllers, which helps with performing many of the MATLAB operations. A Core 2 Quad, while not a bad CPU, will not perform as well as an i7 or Phenom II in this case.

Also, if you get the Phenom II, get an AM3 CPU and motherboard, and use DDR3 memory. The speed boost will actually help in matlab, and DDR3 is not as expensive as it used to be. This would be a good choice:

http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Guys, thanks for answer. Actually it is quite clear for me too, that i7 is one of the best performing cpu for this sort of tasks, but honestly it is well beyond the limit of my budget. And that's the same reason, why I wouldn't buy DDR3 RAM. The above two listed configurations are somewhere around my limit, and I can't and don't want to afford more.

It is true that MATLAB is well threaded in most situations, mainly for linear algebra stuff, matrix-vector operations. It is also sure, that loops are not optimized at all: if the code only contains loops without parallelized matrix-vector operations, it will use only one core.

But what is behind the parallel performance of MATLAB, is mainly the optimized library for both the intel processors and the amd processors. I know that the Intel Math Kernel Library is well-made and very well optimized, but I don't know anything about the AMD Core Math Library. Actually, it also depends on which MATLAB version one uses, but It is true that there are no reliable tests about the MATLAB performance of the newest AMD processors.

I read tests, where AMD Phenom X4 9850 performed worse in MATLAB, then a Phenom X3 8750. I also read opinions, that the AMD Core Math Library should be disabled in MATLAB, and one should switch to the Intel MKL, regardless the precessor brand, as MKL performs better.

http://ixbtlabs.com/articles3/cpu/phenom-x4-matlab-p1.h...
But this all seems to be messy,

and I am full of urban legends and fairy tales, that the AMD phenom 2 X4 _supposed_ to perform 2x..3x...4x...100x faster then Core2 Quad in MATLAB. Does anyone have real comparisons ?

In my opinion, the performance of a cpu in an application is on one hand determined by the cpu it self, and on the other hand (which is not less important) by the optimized or non-optimized code, that it runs. And this is what I don't know, how good the support is for AMD processors in such applications, how good thez run for example with applications compiled with the Intel MKL, or Intel Compiler.