On Thu, Mar 23, 2017 at 1:14 PM, RETRO Innovations via vcf-midatlantic < vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
In my opinion, the 64 ran at 1MHz, because Jack did not have interest in investments needed to make the chip faster. He wanted it cheap and plentiful.
In some respects, this aligned with the original MOS goal. CPUs for the masses, cheap. I am sure the HW guys would have loved to do more R&D, but MOS' tech was "good enough" to support the company, and that's what Jack focused on.
I believe there are -2 and -3 MOS NMOS units and had been for some time, but Jack didn't need fast, he needed fast enough and that was it. Running at 2MHz would have required static RAM or faster DRAM, so 1MHz (essentially 2MHz due to the CPU/GPU bus sharing) was fast enough.
JIm
I think this is why Bill Mensch left MOS and started WDC in '78, and made further improvements in speed and instructions to the 6502 and then later the 65816