Do you remember the old "Windows Thunking" discussions? You may want to ask for both Vista 32 and XP Pro (32 bit.)
I just bought a Dell Studio D540 (Intel Core 2 quad processor Q9400 2.66 GHz, 8 GB RAM, 64 bit Vista) specifically to speed up the data analysis that I'm doing with Matlab. The program I wrote involves a lot of Fourier transforms etc, it takes about an hour to run on my PC at home, an HP s3500f (AMD Athlon dual core 5400 2.8 Ghz, 6 GB RAM, 64 bit Vista), but over 2 hours on my Dell Studio.
According to the benchmarks on the cnet reviews the Dell should be faster than the HP or at least comparable, it should definitely not take twice as long. There has to be something seriously wrong with this system. As a comparison, the program takes about 1 hour 50 mins to run on an old 2.8 GHz Pentium 4 in the lab.
I've tried to get help from Dell but they said it was a software problem & it's not covered by the warranty.
Any ideas for why I'm getting this truly abysmal performance would be greatly appreciated.