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Overclock your megadrive!
Curtis - Mar 10, 2004

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  Curtis Mar 10, 2004
http://www.bluespheer.com/host/epicgaming//hardwar... :thumbs-up:

 mtxblau Mar 11, 2004
Wow, that's pretty neat. But what games are there that the lag gets that bad? Off the top of my head I can't really think of any. Maybe in X-Men2... any others?

 it290 Mar 11, 2004
Thunderforce 4/Lightning Force.. although it's almost needed in some parts. And several other shooters as well (grindstomer for example). Also, it would be cool to play sonic and not have slowdown when you lose all your rings... or Sonic CD without all the excessive slowdown period.

 Alexvrb Mar 11, 2004
I wonder how OCing the genesis would affect Sega CD/32X games?

 racketboy Mar 11, 2004
Gunstar Heroes lags at times when there is a lot of blowing up going on

I should try overclocking some, painting them blue and selling them on eBay as a RARE Limted Collectors Edition Super Sonic Speed Genesis with an extra dose of Blast Processing

 it290 Mar 11, 2004
Yeah, come to think of it, it would probably break a lot of 32x/Sega CD games.

 SamIAm Mar 12, 2004
I'm really curious about this mod. I've got Panorama Cotton on a tototek cart, and it's one game that could really benefit from this. Although the slowdown rarely get's very bad at all, the game actually dips down very often...like half the time you play. In hard mode, it's damn near constant.

I'm kind of a newbie at this stuff, but I'd still really like to give this a shot. I've got a genny 2 I never use anyway. First, though, I'd like to hear from someone else who made this to work, and I'm also curious about how the Sega CD and 32X respond to it. Some more detailed instructions would be cool too, let's hope that guy posts pictures.

 CommanderBubba Mar 12, 2004
If it's so easy to get the CPU on the Genesis working faster, then why didn't the original design engineers build it to have a faster clock speed in the first place??

For that matter, if that CPU is capable of producing 2X to 3X its normal output, why was the chip only rated for the slow speed? I'm not sure I understand this fully...

 Des-ROW Mar 12, 2004

  
	
	

		
		

			Originally posted by it290@Mar 11, 2004 @ 12:19 PM



 Yeah, come to think of it, it would probably break a lot of 32x/Sega CD games.


The processors would not be able to synchronize correctly.

 it290 Mar 12, 2004

  
	
	

		
		

			 If it's so easy to get the CPU on the Genesis working faster, then why didn't the original design engineers build it to have a faster clock speed in the first place??


Well, it's like overclocking anything else. It decreases the life expectancy of the chip, and not all 68000's are able to do it as well as others. Motorola rated the chip at 7mhz, so that's what Sega went with. Kind of like when you buy a Dell, it's not overclocked when you get it.


  
	
	

		
		

			The processors would not be able to synchronize correctly.


Yup, pretty much. Although it would probably work w/some games. And there would probably be a way to do this mod and still retain more compatibility (while still reaping the benefits). The guy did mention a switch method however, which is a good work-around.

 SamIAm Mar 12, 2004
Interesting comment from the slashdot page:

"As I recall, by the end of life the Motorola 68000s were all made as 16MHz parts. The slower parts were simply not made or sold any more. Also, even when they were genuine 8MHz parts, they were pretty reliable with 50% overclocking; we did this sort of thing all the time in Atari STs before the 68020 and 68030 upgrades got popular.

There were limits to what you could gain though, since the 68000 had no on-chip caches of any kind and the system bus generally couldn't handle as much of a speedup. The better upgrades included a memory cache with the accelerated 68000 on a daughterboard that plugged into the original CPU socket, to allow the processor to run at full speed without disturbing the rest of the system..."

Could be the reason why this guy got his up to 16MHz so easily. He said even with all that, the chip only rose a few degrees in temperature, so this would make a lot of sense. Although if it is true, I bet you couldn't overclock a model I MD. Hopefully this would work on most model IIs.

EDIT: Better comment

 it290 Mar 12, 2004
Hmm, interesting. Yeah, that daughterboard type upgrade was exactly what I was thinking for retaining 32x/SCD compatibility.

 Dr_Frankenmiga Mar 12, 2004
From what I remember a 68010 has a 10K cache so that may help and it is pin compatible with the 68000 so that may be a better option.Its also 14Mhz I think cant remember the speed.

Commodore used them to replace faulty 68000`s in A500`s when supplys were tight.Only in repaired models some time in the late 80`s.

Its a rare chip though

 it290 Mar 12, 2004
Wasn't the 68010 standard in the A600? Or did that have an 020?

 Dr_Frankenmiga Mar 12, 2004
No the A600 was a disgrace a hacked up cross between the 500+ and 1200 it was basically a 500+ with PCMICIA port and IDE port for a 2.5" hardrive and that was it the CPU,RAM etc was all A500 (68KCpu and 1Mb RAM)Most came with 2MB and a small hardrive.Oh and some fool removed the NUMERIC Keypad!But there was some accelerators for the A600,they were as rare as hell for 500 series.

The A1200 had the 68EC020 a 020 CPU with 24 bit addressing or somet if I remember,and about 3 times as fast as 68000 I think.

Its not a full 68020 budget reasons,and hence some problems exist because of this.

 Mask of Destiny Mar 12, 2004

  
	
	

		
		

			Originally posted by Des-ROW+Mar 12, 2004 @ 07:57 AM-->
QUOTE(Des-ROW @ Mar 12, 2004 @ 07:57 AM)
 




  
	
	

		
		

			Originally posted by it290+Mar 11, 2004 @ 12:19 PM-->
QUOTE(it290 @ Mar 11, 2004 @ 12:19 PM)
 Yeah, come to think of it, it would probably break a lot of 32x/Sega CD games. [/b]
		

		

	







The processors would not be able to synchronize correctly. [/b]



This is largely dependent on the game. The ones that did proper handshaking would work on an overclocked system; but there are a good number that depend on certain things occuring in order.

In addition there are probably Genesis games that timed things using loops. Such games would likely break on an overclocked Genesis.

QUOTE(Mask of Destiny @ Mar 13, 2004 @ 02:31 AM)

  
	
	

		
		

			Originally posted by Des-ROW@Mar 12, 2004 @ 07:57 AM



 
QUOTE(Alexvrb @ Mar 14, 2004 @ 01:14 AM)
 




  
	
	

		
		

			Originally posted by Mask of Destiny@Mar 13, 2004 @ 02:31 AM



 




  
	
	

		
		

			Originally posted by Des-ROW@Mar 12, 2004 @ 07:57 AM