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Overclocking Your Sega Genesis/MegaDrive
Deven "Epicenter" Gallo writes "I've recently been working on a project to alleviate the slowdown inherent in older game systems. How you ask? By overclocking them! I've managed to perfect overclocking the Sega Genesis / MegaDrive. The processor (a Motorola 68000, running at a stock speed of 7.6 MHz) can be pushed to 16.0 MHz in my experience, and I am still working on higher. The machine doesn't overheat and is entirely stable at these higher speeds."
I don't recall exactly, but I think you could 'overclock' the genesis in older emulators like Genecyst, so perhaps that would be a good way to check to see how well games run overclocked before you actually futz with your real Genny. I would think that many games would have timing problems at a speed greater than stock, particularly those that use raster effects. I can't say for certain, but I know my old Gameboy Color raster effects would break completely if I overclocked them. I would wager that racing games would probably suffer the worst.
Granted, it's nice for the coolness factor, but unlike PCs, newer and flashier games only come out for beefier platforms and can't be run on the old ones anyway, no matter how fast they're going.
Reliability.
You don't want to have to replace thousands of pricey (back then) consoles if chips prematurely fail.
Well you've got to remember that these things were made for several years. Just a guess, but I'm thinking by the time the last ones they sold were made, Motorola probably had long since quit making 7.6mghz chips, and were just shipping whatever their bottom of the line was at the moment and underclocking it.
Also, you have to remember even if that's not the case, there's a lot of variability in chips. Just because this guy got his to run at this speed reliably, doesn't mean they all would.
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"The article apparently claims that it remained stable at over an additional 100%"
Yes, but for how long? Sega wanted their machines to run a few years tops. Overclocking your Genesis CPU and still having it running after a week barely proves that Sega has underpowered it.
this is because of the way the game works
the game does something (AI, moving stuff, updating screen) and then waits for VSYNC since that's the only time it can update video memory.
so in other words your game is synched to a 60 hz clock. even if it finishes the work 1000 ties faster the CPU still waits for a 60Hz signal from the video chip.
If you're programming to a non-upgradable system (like a console), you frequently DO hard code things to hardware parameters. Thats why a lot of old DOS games are now unplayable- they assumed clock speeds were 33 MHz.
I still have more fans than freaks. WTF is wrong with you people?
Ok, short version:
SNES - slow as hell processor, makes up for it with specialized GFX and Sound chips.
Genny - Faster processor, better memory usage, but fewer colors onscreen and no built-in scaling and rotation.
But really, if you aren't running NeoGeo, you're eating squirrel burgers. ;-)
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I am glad to see this as a root post. Anyone who has ever dug into the internals of the Amiga, Mac, or Atari ST hardware has found that moving to faster 680x0 CPUs did not affect game speed, only the amount of lag (we called it "bog") in a game.
;) Hell, we might still be able to see that just for kicks.
I have nearly two decades of experience with the 680x0 CPUs in the Amiga systems. I remember being absolutely thrilled when Sega used the 68000 CPU in the Genesis. I hacked an original unit which had the 68-pin package with a 68010. Honestly, I do not remember the full results, but I recall I was still able to play the majority of my collection (two carts at the time, hahahaha.)
I also toyed with the idea to replace the 68000 with an MTec 68020 accelerator pulled from my Amiga 500. I never tried it, and I still am not so sure it would have worked anyway. If the AmigaOS was a little less hard-wired to the Amiga hardware architecture, given a little work, we might could have seen AmigaOS running on a Genny
Having gone from 68000 to 68040 in all its discernable steps (I still dream of a 68060/PPC accelerator for my A4000,) I have been able to bring all of my games with me. The only problem I have is with expected timing of the OCS chipset versus the AGA chipset. But there are a number of great hard drive installers which over come this, as well as system "degraders" which place the computer in a state almost identical to the original Amiga hardware.
In any case, I'm inspired by this article and look forward to dropping a 12MHz clock generator in my Sega II (provided its CPU will support it.)
(climbing up on soap box) It is also worth mentioning that us old-hat gamers take a lot of shit for being so nostalgic and blah blah blah, aching for an era long-past. I got news for those who cast stones, many of those games were FUN, and down-right phuqn great. I will not say that none of my collections are nostalgic -- I have a number of Atari 2600 carts which I never played then and do not play now other than for testing, simply because they are Atari. But the majority of the games I collect (Amiga, Atari, Sega, NES, TI, C64, and others) WERE fun, and are STILL FUN.
How many people are still playing a "dead" console because the games rocked and you cannot get them for "modern" consoles? PS1 is almost 10 years old, and yet it still has a large following. I bet in 10 years there will still be a large faction of people playing the original XBox because some of the titles will not be available on newer consoles, or just will not play the same. (I do wonder how game play of XBox 1 games will be on the XBox 2...)
Well, enough of that.
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First off, this place is for discussion and it is generally a good idea to counter opinions with your own rather than trying to censure people. Let moderators decide what is and isn't appropriate. That's what the system is for.
Secondly, it appears as if you've created multiple accounts so you can make posts supporting yourself without it appearing as if you're doing (even though it's patently obvious). If this is not the case, I find it to be a remarkable coincidence that three new users with almost consecutive IDs, you (761169), laggerzero (761187) and Light Serif (761190) all commented in the same thread right after one another. Further, those comments were the only ones those users ever made. Quite a coincidence indeed.
Last but not least, and please take this as a constructive suggestion and not an insult: Take a deep breath and try to relax. You're working yourself into a lather unnecessarily and in the process, making yourself look a tad silly. Remember, this isn't a popularity contest. It's just Slashdot.
Is it possible to desolder the 68000 and replace it with a 68010? The '10 had better integer performance and had an identical pinout.
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