Hi, Currently CPUID function 4 is broken. This function's values rely on the value of ECX. To solve the issue cleanly, there is already a new API for cpuid settings, which is not used yet. Using the current interface, the function 4 can be easily passed through, by giving multiple function 4 outputs and increasing the index-identifier on the fly. This does not break compatibility. This fix is really important for Mac OS X, as it requires cache information. Please also see my previous patches for Mac OS X (or rather core duo target) compatibility. Regards, Alex