I got the 1220 (@18Mhz) and have it on a switch to overclock to 26Mhz. It's great for everything I play on it.
I think it's 16.67Mhz (Standard) - but the chip on mine is marked as an 18Mhz version, but then overclocks to 26Mhz.
I will take it apart when I get time and take a pic. It's an extremely simple mod - but you take the risk of overheating your CPU. That said, i've run mine for hours and checked temperature and its barely warm, so I could have a 'good chip', Motorola are well known for basically having single production runs whereby they then speed and stability test chips to work out how best to sell them - ie. at what clock speed.
Wouldnt suprise me if an 18Mhz chip ran OK at 33 or 40Mhz based on how its very luke warm for me at 26Mhz.
Anyway, i've got a red PCB for my 1220 - despite it looking green on their website, I think the latest ones are red (mines 4 months old). With the chips facing upwards and the expansion connector to the left side, if you look to the right hand side just above the RAM and to the right of the CPU there's a little matrix of solder pads. On the standard 1220 config it has the top link jumpered with what I believe is a 1ohm resistor / link. The points are very very tiny to solder on so I recommend a good clean soldering iron and fine Kaynar wire or similar.
If you look elsewhere on the board there's actually a table printed on the board that shows the clock frequencies when certain jumpers are set out of that matrix of 4. Actually 8 pins, 4 lots of 2.
All I did is solder 2 wires, 1 from each end of the very small pads and if memory serves it was the top 2 pads (already joined) and the bottom 2 pads that give 26Mhz, and each wire went to a switch - ie. 1 wire to the middle of a toggle switch, the other to the outer pin of a toggle switch.
JP1 []---[] < already has a 1ohm link / resistor soldered in there
JP2 [] []
JP3 [] []
JP4 [] [] < these are the 2 pads with wires to a switch
That's it, just dont switch when powered up. So now you can toggle between default speed and 26Mhz on the 1220. The switch just shorts those 2 bottom pins (JP4) out which tells the FPGA to run at 26Mhz.
You get a wonderful speed boost for normal operations and some of the more intensive games like Frontier and 3D shooters etc gain enough to become a bit more playable. Just dont expect to be playing Doom etc, you really need 40Mhz+ and actually I think frame rate can suck on anything less than 50Mhz. For the 3 or 4 games like that I am not bothered personally, the 1220 is the best balance of performance vs cost.
