How does that increase the multiplier itself? I was asking if there was any way to change what multiplier it uses, because it is locked at 6. Preferably without ripping anything off the mainboard. But I guess not.mattthemodder wrote:if you change the frequency that goes into where the leg of "CPU Multiplier" goes you'll up it.
Took pics and made an OC diagram
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yeah. overclocking the DC and overclocking your PC are different. in PC overclocking, the mhz raiting stays the same but you increase the multiplier which in turn increases the end-result cpu speed.
in DC overclocking the multiplier is stuck as well as the system bus speed, but increasing the system bus is much easier than trying to increase the multiplier.
in DC overclocking the multiplier is stuck as well as the system bus speed, but increasing the system bus is much easier than trying to increase the multiplier.
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Um.. wtf? When you overclock your CPU on a PC the clock speed (MHz or GHz) increases. Most CPUs are multiplier locked, that's why most people increase the FSB (Front Side Bus).Vchat20 wrote:yeah. overclocking the DC and overclocking your PC are different. in PC overclocking, the mhz raiting stays the same but you increase the multiplier which in turn increases the end-result cpu speed.
Example: Athlon XP 2500+ = 11x multiplier X 166 MHz FSB = 1826 MHz. If you want to overclock it, you'll increase the FSB. If you increase the FSB to 180 Mhz, then the CPU is running at 1980 MHz, becuase 11x multipler X 180 = 1980.
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As has been said, you can do both on many PCs, but otherwise you're stuck with a locked multiplier and have to work with the bus. What I was asking (multiple times) was if there is a way to change the multiplier on the DC without removing and replacing components. The answer is now obviously no, but I was getting a bit sick of being told that you need to change the frequency that it multiplies by 6. No, really? That wasn't what I was asking. So forgive me if I seem a bit vexed. It's just that in the case of the DC, I'd rather be able to run at like 216/232Mhz and keep all the buses the same. That would be enough to give a good speed boost and help eliminate slowdown, without introducing sync issues.
If you have twenty monkeys,
banging randomly on typewriters,
they will in twenty minutes produce the complete source code to World of Warcraft.
banging randomly on typewriters,
they will in twenty minutes produce the complete source code to World of Warcraft.
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The maximum the dreamcast can be overclocked to is 266.66 MHz. I have not attempted to overclock my DC, but I found this document that says the max multiplier is 8. ( 33.33 X 8 ). So theoretically the max is 266.66 MHz without any testing. You would need a 44.44 MHz oscillator ( 44.44 X 6 ) to make it almost 266.66 MHz. You would probably have to raise the voltage also somehow. The document says the max voltage for the SH-4 is 3.6 V (I/O) and 2.0 V internal. If oscillators are put in series, do they combine the MHz or is it divided? So you should be able to put oscillators in series or parallel to combine MHz. One or the other should work? http://mc.pp.se/dc/files/h14th002d2.pdf
I found this at http://mc.pp.se/dc/hw.html under Hitachi SuperH SH-4. There are two more documents.
I found this at http://mc.pp.se/dc/hw.html under Hitachi SuperH SH-4. There are two more documents.
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Those numbers are irrelevant unless you're building a new system based on whichever SH4 model that manual is referring to. You see, we're not touching the multiplier, we can't change it. We can only change the frequency that is multiplied by 6. So nothing holds us down to a set number like 266.66Mhz. There are limits, but they have nothing to do with that. Also that voltage "max" means little as well. My K7 CPU is specified for a given voltage, but that doesn't mean I can't overvolt the hell out of it if I so please, it is limited not by the CPU, but by whatever I feel like feeding it (until the board can no longer supply any more, or it burns out). The problem is finding a way to change the voltage fed to it in the first place.
If you have twenty monkeys,
banging randomly on typewriters,
they will in twenty minutes produce the complete source code to World of Warcraft.
banging randomly on typewriters,
they will in twenty minutes produce the complete source code to World of Warcraft.
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http://nifty.amikai.com/amiweb/browser. ... c_id=nifty
^original guide partially translated, much more comprehensive than the English one.
^original guide partially translated, much more comprehensive than the English one.
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Here's a diagram I did to overclock my dc : tested =)
Here is a diagram I did of what you should do to overclock your dreamcast to 240MHZ with a switch... Personnaly I did it but my buddy broked the lifted pin so my spare dc will now always be overclocked by he way I order another motherboard for 3$ so i'll OC it back
Here's the diagram:
I Wish you'll like it !!
Here's the diagram:
I Wish you'll like it !!
Last edited by FamilyGuy on Wed Aug 30, 2006 4:15 pm, edited 2 times in total.
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lol .. maybe yeah just don't really know how this switch work I mean ... the central pin is output .. 2 other pin are inputs.. but I dunno if to put the pin right will make the left or right input to be the one to be connect
By the way here's a picture of my own overcolcked dreamcast
It's overclocked at 240Mhz and it works fine.
There's not switch to go back to 200Mhz ... beacause :1-I don't have a switch right now... 2-This motherboard was broken ... because the 33.33Mhz signal wasn't working lol
Here's the picture:
Hey Semicolo: c l'fun de voir un Qu?becois su un forum ... sa faisait longtemps jnava pas vu ...[/img]
By the way here's a picture of my own overcolcked dreamcast
It's overclocked at 240Mhz and it works fine.
There's not switch to go back to 200Mhz ... beacause :1-I don't have a switch right now... 2-This motherboard was broken ... because the 33.33Mhz signal wasn't working lol
Here's the picture:
Hey Semicolo: c l'fun de voir un Qu?becois su un forum ... sa faisait longtemps jnava pas vu ...[/img]
Last edited by FamilyGuy on Wed Aug 30, 2006 4:27 pm, edited 3 times in total.
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Who did it ??
Hey I want to know ... who overcloked his DC ??
I did .. who else did in this forum ?? I saw the topics is somewhat old so ...
Just wondering ...
I did .. who else did in this forum ?? I saw the topics is somewhat old so ...
Just wondering ...
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I've just do this OC'ed dreamcast with FamilyGuy ...
Hi dude !!
Hi dude !!
Last edited by Lil' Jimmy on Tue Aug 15, 2006 12:37 pm, edited 1 time in total.
- FamilyGuy
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I'm gonna try this one as soon as i'll get the parts ... ( switch and Xtal are hard to find in my location)
Wish me GoodLuck...
EDIT: this didn't worked ... the 48Mhz signal seems too high .. will try lower .. the Scheme will work with any other Xtal value.
Wish me GoodLuck...
EDIT: this didn't worked ... the 48Mhz signal seems too high .. will try lower .. the Scheme will work with any other Xtal value.
Last edited by FamilyGuy on Wed Aug 30, 2006 4:25 pm, edited 1 time in total.
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How many times do I have to tell you all, the 54Mhz signal is NOT the graphics clock! The graphics clock is simply drawn from the 33Mhz signal as well. The 54Mhz signal is for frame buffer.
I was told that by the person who designed the god damned "GPU".
I believe that makes the 3rd time I have said that
I was told that by the person who designed the god damned "GPU".
I believe that makes the 3rd time I have said that