Some C4Ds, Stocks etc can be 56k.
And if the new canvas lag to you, you should clean up your temporal files.
Defrag the system...
Is your PS like LEGIT or cracked?
this happened to me like a week ago turns out i put inches instead of pixels and i didnt notice drawing a line would lag make sure thats not whats happening
idk but i wouldnt doubt that some cracks may cause a lag or w.e. idk.