Be careful with minimum specs also. These are often the absolute minimum and won't allow you to do anything else. I agree that the Minimoog VST will be heavier on CPU. However, I believe that Charlie is sample-based and will most likely be heavier on RAM. 256 MB of RAM will not get you very far these days with the current tools. You need to seriously look at upgrading that PC before investing too much in the latest VST's and sample-based instruments IMHO.