My daughter uses a program that need high single core speed. I don't know if it is solidworks, or what.
What you are looking for is the best single core performance, and overclocking would be a bonus.
> 2.7GHz vs 3.1-4.5GHz chip
Performance is fairly linear when comparing clock speeds (all else being equal). You probably won't notice 2.7 vs 3.1 (15% difference), but you will notice 2.7 vs 4.5 (67% difference).
Cache is also important for Solidworks. If the 2.7 has more cache than the 3.1, then go for the Cache.
> I couldn't find much info on favoring for GPUs
Get the fastest card you can afford that is Solidworks Certified compatible.
http://blogs.solidworks.com/solidwor...rformance.html