MATLAB on Windows7 vs UNIX

Hi, I have been having this problem of extremely slow MATLAB operations on my super workstation (3.46 GHz, 6 core, 12 GB RAM) with RHEL 5.5 64 Bit OS vs. my timid laptop (2.20 GHz, 4 core 8 GB RAM) with windows7 64 bit OS. So, I am a working in Computer vision subspace based methods which means I frequently run into eigen-value problems of all sizes big and small. So, I now needed to do eigen-value analysis of big matrices so my adviser got me the workstation cause my laptop was extremely slow and ran into memory problems with matrices of size 25000 by 25000. The workstation although was able to get around the memory problem but I found it extremely slow as compared to my laptop which is weird when we compare the configurations. To dig into deep I ran some experiments and found out that actually MATLAB is slow. I just used it for simple eigen-value computation on some randomly generated matrices of big sizes and compared the time and found out that MATLAB on my workstation was actually taking up almost double the time. Can anyone explain it pls (All the experiments were ran on matlab r2011a 64 bit version both on windows and UNIX).

a = randn(x,50);
b = a*a';
tic; [ev ed] = eigs(b,40); t = toc

             laptop                     workstation
x = 7000     2.5615 sec                  4.1247 sec
x = 10000    5.5642 sec                  6.6114 sec
x = 12000    8.1123 sec                 11.2058 sec
x = 15000   12.5128 sec                 18.2205 sec

Answer 1

[Walter Roberson]

Out of curiosity: try editing the MAX_NUM_THREADS preference on the 6 core machine to limit to 4 cores and try again.

Answer 2

[Abhishek]

Hi, I tried this suggestion and here is the summary of the results I got using the suggestion ---

             4 core       6 core 
--------------------------------------------- 
x = 7000     3.8791       4.1247 
x = 10000    7.1148       6.6114 
x = 12000    11.4470      11.2058 
x = 15000    17.8545      18.2205 
---------------------------------------------

Still not equal to windows performance in spite of the fact that there is a huge difference in terms of hardware quality. Regards Abhishek