Costis is screwing around with the clock on a GBC and I just couldn’t keep myself from trying it out. He quoted some pretty insane max clock speed and I wanted to see whether it would really go that high. Turns out it goes pretty high: ~24Mhz (~3x) for GBC games, and ~48Mhz (~6x) (!) for GB games. Normal speed is 8.338Mhz input, though GB games internally run at half speed (~4Mhz), which is why they can run much faster. This is just a GBC hooked up to a frequency generator implemented on a Spartan-3E starter kit. No extra mods were done to the GBC. I plugged in my desktop speakers to the audio jack so you can hear it better. The BIOS ROM can actually run at over 70Mhz but the screen glitches up pretty weirdly and my setup is too crappy to make it stable. At those speeds the drive strength on the FPGA and other details start to become much more important. Costis’ work: www.its.caltech.edu Improved frequency generator for S3EBOARD: marcansoft.com