Which should I choose for normal use
The Ryzen 3600X will likely give you the better solidworks performance. This is based on the speed that they run single threaded tasks. PassMark - CPU Comparison AMD Ryzen 5 3600X vs Intel i5-9600K
Lots of other components are also important for SW performance most notably is the GPU. Make sure to get one that has certified drivers for SW. SOLIDWORKS Hardware Certification | Hardware & System Requirements | SOLIDWORKS
No other real tricks with the rest of the hardware but of course RAM and storage speed are important especially so if you plan to do 'large assembly' modeling.
Hope that helps.
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