Official DC Overclocking thread
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- DCEmu Cool Newbie
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Official DC Overclocking thread
Hello!
I'm sure most of you have seen the overclocking tutorial I wrote a few years ago featured on Devcast. I get all kinds of questions about the procedure, results, etc...
My time has become increasingly limited, so I wanted to post this thread to allow people to ask me questions relating to this particular mod. Thanks!
-Rob
I'm sure most of you have seen the overclocking tutorial I wrote a few years ago featured on Devcast. I get all kinds of questions about the procedure, results, etc...
My time has become increasingly limited, so I wanted to post this thread to allow people to ask me questions relating to this particular mod. Thanks!
-Rob
J-Gen: JAMMA Genesis project
- Morphv2
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I believe matthemodder hit 286. You'd have to do some looking, or asking.
I have hit very high clockspeeds, but stability takes a nosedive after 276Mhz. From our assumptions at dcdev, 2 things could be holding it back from clocking higher:
1. CPU voltage
2. Slow memory
It is possible that the vcore line was located, but the memory is another story.
On most models, the system memory is rated for 10ns, which means it was rated for 100Mhz only. A lot of the time, the GPU and Sound memory is rated for 8ns aka 125Mhz, which means you aren't technically "overclocking" that memory until you peak over 125Mhz. However, the fact that your system memory is only rated for 100Mhz operation, means that ANY increase in speed is pushing it over designed specifications.
I have a board with 9ns memory for everything, but lord knows if the oddball even works.
I have hit very high clockspeeds, but stability takes a nosedive after 276Mhz. From our assumptions at dcdev, 2 things could be holding it back from clocking higher:
1. CPU voltage
2. Slow memory
It is possible that the vcore line was located, but the memory is another story.
On most models, the system memory is rated for 10ns, which means it was rated for 100Mhz only. A lot of the time, the GPU and Sound memory is rated for 8ns aka 125Mhz, which means you aren't technically "overclocking" that memory until you peak over 125Mhz. However, the fact that your system memory is only rated for 100Mhz operation, means that ANY increase in speed is pushing it over designed specifications.
I have a board with 9ns memory for everything, but lord knows if the oddball even works.
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- DCEmu Fast Newbie
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well, lets say i do overclock my dc, where would you get the oscillator?
is this correct?
http://www.cascadesurplus.com/catalog/p ... cts_id=631
or would an electric store have one?
is this correct?
http://www.cascadesurplus.com/catalog/p ... cts_id=631
or would an electric store have one?
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- DCEmu Cool Newbie
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Digikey.com sells them, but if you want to go absolutely cheap, you can salvage them from old circuit boards.
If overclocking is something you might do to other systems, you can get some good bulk-buys on ebay. Only the 4-pin variety will work.
(Note: the other 2 pins aren't visible in this pic)
If overclocking is something you might do to other systems, you can get some good bulk-buys on ebay. Only the 4-pin variety will work.
(Note: the other 2 pins aren't visible in this pic)
J-Gen: JAMMA Genesis project
- Morphv2
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I generally just use Ebay myself. WE're talking you can get these things in BULK for like $10-$20.
Also, prophet, I kinda jimmied myself a "switch" together. It's not completely variable, but you get the idea. It contains 3 oscillators (37Mhz, 40Mhz, 45Mhz) inside a cheapo Radio Shack housing, all soldered to a small PCB with 4 switches (one for each clockspeed, Normal, 112Mhz, 120Mhz, and 135Mhz). It's bolted to the side of the DC itself, with a small hole drilled into the side of the DC, and the side of the housing to run the necessarry wires through.
It's crude, but it works like a dandy.
Also, prophet, I kinda jimmied myself a "switch" together. It's not completely variable, but you get the idea. It contains 3 oscillators (37Mhz, 40Mhz, 45Mhz) inside a cheapo Radio Shack housing, all soldered to a small PCB with 4 switches (one for each clockspeed, Normal, 112Mhz, 120Mhz, and 135Mhz). It's bolted to the side of the DC itself, with a small hole drilled into the side of the DC, and the side of the housing to run the necessarry wires through.
It's crude, but it works like a dandy.
- FamilyGuy
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I bet you mean Normal, 222, 240, and 270,4 switches (one for each clockspeed, Normal, 112Mhz, 120Mhz, and 135Mhz)
Because the DC multiplier is 6, so 6*37, 6*40, and 6*45.
Does the 45mhz works well ??
I tried it at 48Mhz but I got a black screen.
40Mhz works perfectly thought.
I'm working on a synch'd VMU
- Morphv2
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I rate by front side bus speed, not the entire clockspeed. When I overclock the DC, like a computer, I am overclocking the whole bus, not just the CPU. Also, its a multiplier of 2. The clock signal is multiplied by 3 from the PLL (for the FSB), then further by 2 for the CPU.
You'll have to show me how to sync a VMU, I use a Nexus part I got from Newegg (r.i.p.) with a USB cable. I usually save directly to a computer with it. It'd be much better to use a solution like yours.
Once I cut the procrastination, I'll do a video. For me, 270Mhz works fine, although I get occaisional corruption. In dcemu, we have a far more detailed thread on the subject.
You'll have to show me how to sync a VMU, I use a Nexus part I got from Newegg (r.i.p.) with a USB cable. I usually save directly to a computer with it. It'd be much better to use a solution like yours.
Once I cut the procrastination, I'll do a video. For me, 270Mhz works fine, although I get occaisional corruption. In dcemu, we have a far more detailed thread on the subject.
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- DCEmu Cool Newbie
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Well whenever I overclock a Dreamcast I always turn it on once I disconnect the stock clock signal to ensure it will *not* boot. So when I hook up my new speed and it boots, I know it's running on the faster speed. If you have a game that is nutorious for slowdown like Shenmue, Psyvariar 2, or Sega bass Fishing, you can generally see an increase in performance.muthafied wrote:Hi there don't know much about overclocking a dc, so how do you know if you have successfully overclocked a dc apart from the game speed and is it true that you can't use your vmu once your dc has been overclocked? Thanks.
As for the VMU issue, i've never tested this, does it not function?
J-Gen: JAMMA Genesis project
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http://cgi.ebay.co.uk/SMT-SMD-40MHz-CRY ... dZViewItemmiggi03 wrote:Hi there, some of the links to the oscillator needed are outdated. Anyone know where i can pick one up? I live in the Uk been googling all afternoon to but no luck and ebay ain't got any. Thanks.
40 MHz part, this would make your Dreamcast run at 240 MHz. Auction ends in ~4 days.
J-Gen: JAMMA Genesis project
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Thanks bought it just now.
[img=http://img246.imageshack.us/img246/6788 ... ut5.th.jpg]
EDIT, still waiting on the crystal, *sigh* as soon as the mods done ill post the results.
[img=http://img246.imageshack.us/img246/6788 ... ut5.th.jpg]
EDIT, still waiting on the crystal, *sigh* as soon as the mods done ill post the results.
Last edited by miggi03 on Thu Dec 14, 2006 5:55 am, edited 1 time in total.