US SNES games all had a vertical line on the shrinkwrap on the back that's basically next to impossible to replicate so it's pretty easy to tell real factory sealed ones.
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Nah, I used to easily reshrink wrap SNES games with the line in the back. I didn't have a machine - just a soldering iron, metal ruler, and a heat gun.
Anyway, someone mentioned the SNES running at 3.58mhz. That's in fast ROM mode - early(and most) SNES roms used slower ROMs that set the CPU to 2.79mhz and some were combo fast/slow rom carts. SNES's PPU is pretty amazing though while it's CPU is slow and lacking any additional custom CPU opcodes. One thing the SNES did have was a fairly fast multiply/divide IC that the CPU accessed via ports - though still not as fast as a lookup table.
The SNES's sPPU had a mode to do 8bit tiles(256colors) which is why the 60fps mode 7 effects looked nice, while the SegaCD was limited to one 16 color palette for *all* the scaling/rotation and was limited to 30fps at best (small window) and much less FPS for full screen window(scaling/rotation). What a waste of cost.
But.. NES for the win. While the SNES graphics were beautiful, a lot of the games were just came off as generic feeling. NES had much more fun and memorable games.