CPU Overclock

Discussion in 'Xbox (Original console)' started by kingkat, Jan 29, 2014.

  1. kingkat

    kingkat Robust Member

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    I've seen people talking about overclocking their Original Xbox's CPU for the Mame128X app. Just wondering if this is possible and what are the outcomes. I may have to do this and the RAM mod for a 1.4 Console.
     
  2. Borman

    Borman Digital Games Curator

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    Ive never seen anyone mention that, ever hah. They have upgraded CPUs, sure, but no overclocking that I know of.
     
  3. sonicdude10

    sonicdude10 So long AG and thanks for all the fish!

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    Overclocking the Xbox CPU? Never found anything and I've looked. Maybe someone else who has looked deeper might know something.

    I do know the Friendtech Dream X 1480 was overclocked. The 1.4Ghz Tualatin CPU in it was clocked to 1.48Ghz hence the 1480 part of the name. Still don't know what they did to make that and the half power 740Mhz mode possible.
     
  4. davidthomas

    davidthomas Site Supporter 2013,2014

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    They cut the Front Side Bus in half to get the 740MHz speed.
     
  5. sonicdude10

    sonicdude10 So long AG and thanks for all the fish!

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    I'm not quite so sure. I've heard it discussed and seem tech documentation of the Tualatin CPU that says the 740Mhz mode was done by cutting the instruction cycle in half. Or something to that effect. Can't remember...
     
  6. davidthomas

    davidthomas Site Supporter 2013,2014

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    I want to buy a friendtech 1480! Now that would be the crown jewel of my collection! What is the value of one?
     
  7. kingkat

    kingkat Robust Member

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    So is it possible for me to buy/ make one of these upgraded CPUs? If it requires reballing it to the motherboard then I am fine with that.
     
  8. sonicdude10

    sonicdude10 So long AG and thanks for all the fish!

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    It is but the way Friendtech did it to the 1480 was a special adapter. What I know is the adapter has a switch to do something to the instruction line cutting out every other one to essentially cut the speed of the CPU in half without lowering the FSB. As for the the overclock it has, I think they somehow raised the FSB on the console and possibly altered the multiplier too. The CPU used is the Pentium 3 Tualatin and that comes clocked at 1.4Ghz by default. They bumped it up to 1.48Ghz it seems. So the adapters they used consisted of a mobile socket adapter on the Xbox PCB followed by their own design that switched it over to the desktop socket and had the hardware for the turbo, normal mode switch. Pictures of the insides of a 1480 showed that the wires from the turbo switch went straight to the adapter board.

    So unless someone can figure out how that adapter works and how they got the CPU overclocked to 1.48Ghz then we'll have to stick with the 1.4Ghz only mod that Trusty and others do.
     
  9. APE

    APE Site Supporter 2015

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    You make a false assumption that it's "overclocked". 1.4ghz is what it is marketed at because it's a nice, even number. 133mhz*11=1463mhz and accounting for some slight variations on everything you will see it on the nominal clock rate. And really you'd think they'd overclock the processor a whole 80mhz? Risk instability for such a tiny gain? The actual value apparently is 1481.20000Mhz according to an old XBMC log file too so if you want to split hairs it's the Friendtech 1481.2, not 1480.

    Best I can recall they NOP'd (or effectively NOP'd) every other instruction on the CPU to get it to "740mhz". I don't have any idea how it was done offhand as I've never seen the inside of one of these things and nobody did a teardown from what I can recall.


    Another point, the offical spec puts the XBox at 733mhz. 733/133=5.5112781954887218045112781954887. That's a pretty ugly multiplier and if you instead took 5.5 you get 731.5mhz.
     
    Last edited: Jan 30, 2014
  10. kingkat

    kingkat Robust Member

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    Thanks for the info. So this mod is not documented and I would not experience any severely noticeable benefits? I have heard that with increasing the clock will make most game non-functional. I think I'll just go with the 128mb mod.
     
  11. davidthomas

    davidthomas Site Supporter 2013,2014

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    Well not function is not how I would put it. Some games can run to fast if they use the CPU for timing. But you can patch the .xbe file and that will allow it to run correct. But it can be a pain in the rear if you have to patch alot of games!

    BTW there are 3 tools that are out there to help with upgrades.

    1.4GHz CPU patch
    1.0GHz CPU patch
    128 RAM delimit patch
     
    Last edited: Jan 30, 2014
  12. APE

    APE Site Supporter 2015

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    There is no overclock mod. Period, end of story.

    There is CPU replacement.
     
  13. sonicdude10

    sonicdude10 So long AG and thanks for all the fish!

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    Well Friendtech did SOMETHING to the CPU clock on their consoles. you say the CPU runs at 1481.2MHz in the DreamX 1480? My Trusty modded console with the same CPU runs just shy of 1.4GHz. I got a max clock of 1399.25MHz a few hours ago.

    So what does that mean?
     
    Last edited: Feb 1, 2014
  14. tkeely4777

    tkeely4777 Rapidly Rising Member

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    Does anyone happen to know if Trusty is still offering his upgrade service, and what is involved to have that done?
     
  15. Master13

    Master13 Spirited Member

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    Sure does. You can either send him your board or xbox or he can sell you a pre done board
     
  16. HEX1GON

    HEX1GON FREEZE! Scumbag

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    He's on the forums now, can send him a PM through here too.
     
  17. davidthomas

    davidthomas Site Supporter 2013,2014

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    Trusty is the man with the CPU upgrades. If you get a 1.4GHz from him you should get the speed control switch also!
     
  18. APE

    APE Site Supporter 2015

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    For the clock control: They used a feature of the PIII that forces what amounts to a NOP every other cycle. Apparently it can be enabled/disabled with a wire on a pin.

    As for the exact numbers: read up on how clock signals are generated and you'll find out that there is no such thing as a 100% perfect clock.
     
    Last edited: Mar 14, 2014

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