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How much did IBM save by limiting the PC to 4.77 MHz?

Worshipping at the altar of color clock Back in that day, everything was built around the NTSC color clock frequency of 3.579545 MHz. Everything from the Atari VCS to the C64 made ample use of it, ...
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36 votes
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How can I overclock my Commodore 64?

The basic principle behind overclocking is that if you speed up a clock, everything that runs from that clock will go faster. But there are some parts of your computer that you don't want to speed up,...
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28 votes

How much did IBM save by limiting the PC to 4.77 MHz?

For many kinds of parts, there's a substantial gap between specified maximum/minimum timings and typical timings. The 8088 specification requires that the clock be high for a minimum of 69 ns every ...
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How much did IBM save by limiting the PC to 4.77 MHz?

Quartz used in colour TVs such as 3.579545MHz or 14.31818MHz used to be much cheaper than other frequencies. It was important for home computers and game consoles (8/16 bits), which used the same ...
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If the Sega Genesis/MegaDrive could be overclocked so easily, why couldn't the SNES?

The Super NES (SNES) has a much different hardware architecture than the Sega Genesis, and is built around the custom Ricoh 5A22 ASIC. As opposed to the discrete, stock, Motorola 68000 CPU employed in ...
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12 votes

How can I overclock my Commodore 64?

To get a faster operation there are several "extensions" around, which are either connected to the extension slot or replacing the CPU on its socket working like a coprocessor. CMD's SuperCPU, Flash 8,...
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Overclocking an 8-bit computer

If you're changing just CPU clock speed, leaving the other components as is then amongst those that would continue to read tapes correctly are: The Vic-20 and the Commodore 64. In the case of the Vic-...
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9 votes

Overclocking an 8-bit computer

Since you mentioned the Apple II, it is worth pointing out that accelerators were available for that platform "back in the day". I can speak to how the CPU replacement ones worked (e.g. Zip/RocketChip)...
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8 votes

Overclocking an 8-bit computer

And the main problem here is that in most cases, you'll have to overclock the entire computer, not just the CPU. For example, in ZX Spectrum CPU clock is generated by ULA, so you'll have to overclock ...
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CPU slaves on a PCI card to retrofit single processor to multiple processors. Any ideas how?

how I can add additional slave processors (and possibly RAM) to this system through the mainboard's PCI card slots While DMA works through PCI, this is not practical to sustain to have additional ...
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6 votes

Overclocking an 8-bit computer

I think your bigger problem is going to be dynamic RAM refresh. Particularly in Z-80 systems where the CPU controls DRAM timing, overclocking already tight memory timing specs are undoubtedly going ...
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5 votes

If the Sega Genesis/MegaDrive could be overclocked so easily, why couldn't the SNES?

It's an issue of integration. On the early Genesis systems the custom chips and CPU were physically separate from each other so it was easy to isolate the various clock signals and replace the CPU ...
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5 votes
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CPU slaves on a PCI card to retrofit single processor to multiple processors. Any ideas how?

CompuPro did this in the olden days, with 8-bit and 16-bit CPU slave cards with a 16-bit or 32-bit main CPU. But there were a few differences from what you are suggesting: Each CPU had its own RAM. ...
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How much did IBM save by limiting the PC to 4.77 MHz?

The earlier answers correctly say that IBM chose to divide the 14.3818 MHz NTSC color clock by 3. This decision had nothing to do with CGA graphics, however (whose TV output was asynchronous anyway). ...
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3 votes

How can I overclock my Commodore 64?

It's doable if you have a lot of time, decent electronics skills, and some good test kit to figure out how the VIC video chip and the 6510 share the address and data bus. If I remember correctly, the ...
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