Commodore Speed Limits

I have owned a Commodore 64 computer along with many peripherals for several years. I am happy with my system; however, I have been trying for some time to speed up my machine. From what I understand, the 6510 microprocessor comes in two versions, 1 MHz and 2 MHz. The version in the 64 is the 1 megahertz (MHz) type. Would it be possible to just pull out the old 6510 and replace it with a 2 MHz chip? Would this cause problems with the VIC-II video chip? Any information you can give me regarding possible circuit changes or kits available to do this would be greatly appreciated.

Ed Federmeyer

First of all, the microprocessor itself does not control the speed at which the system operates. The processor's speed is determined by separate circuitry called the system clock. The clock rate determines the operating speed of the computer. The 2MHz 6510 chip is simply a version that is rated as capable of operating at clock speeds of up to 2MHz; plugging in a new processor won't change the way the computer performs.

In theory, you can double the operating speed by doubling the clock frequency. However, this opens the floodgates to a wave of other problems. For example, the 64's VIC-II video chip will produce a usable video signal only if operated at one particular clock speed. (The 128's dualspeed VIC chip can't be substituted; it has a different pin configuration.) Since the VIC-II also includes a portion of the clock circuitry, the operating speed of the 64 is graven in silicon and can't be changed.