In regard to Solidworks Performance, Solidworks as a CAD package uses single thread so unsurprisingly higher frequency CPU s will perform better no matter how many cores you have. For Solidworks analysis tools like Flow Simulation memory becomes key with cores and frequency. In other words a single channel memory will be significantly slower than dual and much slower than quad. If all you want is CAD go for highest frequency. If you want to draw and then test in Solidworks go for core count, high frequency and quad memory at the highest frequency possible.