Note that 3D modelling applications are single-threaded so the number of cores is irrelevant for SketchUp. That is why, too, the graphics card type is not too important provided the minimum requirements are met, as an ultracool whizbang card will sit idle waiting for the CPU. Your model simply has too many edges and faces to run smoothly.
Will help with multi tasking (PhotoShop + SU +…), hi res renders.
I am not an expert on this, but if you copy 1 of the blocks in your model and paste it 5 miles away - you will likely increase lag to the point of making the model unusable.
just right click on the task bar in windows to open the task mgr.
You may not be able to resolve anything yourself with this info, but at least you can see whether or not your expensive GPU is pulling it’s own weight.