Well. I've been playing through a bunch of games, but this just started. I was playing Megaman 7, and if there was too much on the screen, the game would slow to a crawl, which I don't remember while I had an original cart. Now, I'm trying to do a complete playthrough of Pocky & Rocky, and on level 4 and 5 I have the exact same issue, extreme lag (game speed is easily cut in 3/4, as if it's running at 20 fps). Is this normal? I don't remember any lag in either of these games, yet the Superdrive seems to be having it. Can anyone confirm this for me, or should is there a way to fix this?
Most likely this is normal and you just don't remember. Also if you really mean, when I played it on my emulator (such as ZSNES or SNES9X) you don't remember slowdown, this is because many emulators do not emulate various timings properly and slowdown less than the real system. There is no fix.
The Super EverDrive isn't doing any processing, the SNES is. So maybe I am wrong, but I am unsure how the Super EverDrive could cause game slowdown unless there is a problem with the ROM file itself. Slow down happens sometimes in these older games with a lot of sprites on the screen.