So with a discrete GPU working for you, you should not be experiencing slow performance unless the files you work on are rather complex and large in scope. I have a 2011 MacBook Pro with a AMD FirePro and same CPU clock speed as yours, and it chugs along okay until I throw too much at it. Changing from GPU to CPU based view should tell you all you need to know. If it becomes impossible to work in, you're laptop's CPU is bottlenecking performance.
Performance is based on how complex the file is.
If you're having issues with drop shadows in Illustrator, it's probably because you haven't realized that drop shadows are a raster effect. You're working on a large sign in full scale and your raster effects resolution is set to the default 300ppi, so Illustrator is generating enormous rasters for your drop shadows. Go to Effects > Document Raster Effects and set it to 150 or 100 or 75.