Replacing a Signetics 68000 with a Motorola 68000

[alec006]

So I wanted to open my Genesis and see which board revision I have so I could get a capacitor replacement soon. I started looking at the various chips on the board and found my motherboard has a Signetics SCN68000C8N64 CPU rather than a Motorola MC68000.

My question is, would there be any reason to replace the CPU with a genuine 68000, and does an actual 68000 have advantages over the Signetics CPU?

[bust3dstr8]

As long as the chip is 8Mhz or faster it won't matter who manufactured it.

[RP2A03]

From what I understand it only makes a difference if you are going to overclock it. Some also claim the sound is slightly better with a Motorola.

[FABombjoy]

Some also claim the sound is slightly better with a Motorola.
This must be more about the Genesis PCB revision than the main CPU manufacturer.

[APE992]

This must be more about the Genesis PCB revision than the main CPU manufacturer.

Probably given the different revisions did modify what ICs were used for sound IIRC.

I've been tempted to try socketing the 68k and putting a 68030 in there for kicks.

[alec006]

Probably given the different revisions did modify what ICs were used for sound IIRC.

I've been tempted to try socketing the 68k and putting a 68030 in there for kicks.

Would that actually work? I've heard of some people upgrading to the 68010 for a slight speed boost and better overclocking but supposedly it's not 100% compatible.

That being said, I'd like to see if the Genesis would even run a 68030, I mean theoretically it should work since it's the almost the same processor with just a few improvements. Just different instruction sets right?

I think I'll stick with the original 68000 thou, just need someone to install a socket for me when I get my board recapped, I may look to you for that APE992 when I get some extra money :)

[APE992]

Oh it works but it does seem to break compatibility with some games. I can't name any offhand but the 68030 is nearly 1:1 compatible with a greater efficiency per cycle for code execution. I've read that people feel it is comparable to overclocking a Genesis to 10mhz - obviously a 10mhz crystal is a lot easier to find than a DIP 68030 but I'd be doing it for kicks rather than practicality.

And I'd be happy to socket your board and recap it if you don't do it yourself. I probably have the majority of caps needed on hand already from buying massive amounts for various repair jobs.