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Guest jase439

OT: Calling All Overclocking Wizards...

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I am trying to O/C my P4 from 2.40 to 2.70 (original FSB is 133 Mhz on an 845G chipset) by raising my FSB to 150. I am using an MSI 845G-Max L 533Mhz mainboard.Both CPU and Memory (Corsair PC3200 DDR 400Mhz, 2-2-2-5)appear to be very stable and survive numerous torture tests w/o any adjustments to voltages. The voltages coming off the PSU (Antec 430W TruePower) are as spot on as I've ever seen them +/- 0.1v. The system and Windows XP boot normally at 150 FSB. The problem is with the video. I have a Leadtek Ti4400 in this box. At 150 FSB, I lose my video signal entirely on a warm boot. On a cold boot, the system will load normally. The system will run for several minutes this way. Eventually, during a drawing operation (just maximizing a window, for instance), the display will freeze mid-paint and I'll have to reboot. At 145FSB, I can cold boot and warm boot normally and 2D drawing, including DirectDraw applications work fine. Direct3D apps, however, freeze instantly (almost always when the screen resolution is first changed or the first texture is loaded into memory). Even at 143FSB, Direct3D apps will freeze after a few seconds of running. I have tried adjusting AGP voltages from 1.5 to 1.8 without success. Just for giggles, I also tried increasing CPU voltage as high as 1.625v, and DDR voltage up through 2.7v, changed to more conservative memory timings, all with no favorable effect on system stability. I even tried underclcocking the video card. There are dozens of people running GF4 cards at FSB's much higher than 150, let alone 143. What's the secret - I'm all out of ideas. Thanks for any tips. Cheers, JPS. Maybe Mike T. can chime in here now that he is clearly king-of-the-mountain with his big bad water-cooled dilithium powered system ;-)

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Does your board support locking of the AGP/PCI frequency? I run my FSB at 150, but the AGP/PCI stays at 66.66/33.33. Perhaps the card doesn't like the higher bus speeds?

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Not to my knowledge. I think it just applies fixed multipliers against the FSB (which is configurable in increments of 1Mhz) for PCI, AGP, and Memory.I think you're right though. I think my card is revolting against the 75Mhz AGP bus. I wonder if I fiddled with the PCI Latency Timer (presently 32) if it would have any impact. Maybe I'm just running on the wrong motherboard. I bought this board *because* it received high marks for overclocking configurability. Seems like the "other" brands have more configurability. PCI bus locking being one such option.J

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That's a shame, I have a feeling it could be the increased bus speed to the AGP personally. I have had two P4 boards, both have the ability to lock the AGP/PCI, they're the Asus P4B533 and the Abit BD7-II.I ran my old P4B @ 166 with a Ti4600 and no problems, possibly because the AGP/PCI was locked. Do you have anyone else with another motherboard you could perhaps test the videocard in to make sure it's not actually a card issue?

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I'm also considering boosting my P4 2.2 to 2.9 by increasing my FSB from 100 (400) to 133 (533), but I have no idea how to do it. The computer I bought is a Packard Bell, and the CMOS seems to lack any options for configuring the FSB! Is there any way around this, such as a hardware setting?Any help would be greatly appreciated!In answer to your question, sometimes 3d card errors can occur when the FSB is increased by a non-compatible amount, and you'll find that increasing the FSB to beyond 150, say 155, may actually fix this problem. The Pentium 4 is highly scalable and capable of extreme amounts of overclocking, and automatically throttles down if you accidently overheat it, so you might want to try overclocking the FSB to slightly above 150, if the motherboard supports it!From memory I don't think there is any way to increase the CPU multiplier on the Pentium 4, either, which can be a pain.Good luck!James

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If your bios has no adjustment for fsb, then you must change it with jumpers on the mainboard. If you have no mainboard manual, perhaps there is one online, and perhaps packard bell commissioned a custom mainboard that doesn't provide jumpers.Good luck.

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Well, it was a good idea. Alas, however. I tried 155 and the system wouldn't even POST. No video signal at all. Not even a green light on the monitor. I tried 160 and 166 just for giggles and laughs, and I think the BIOS must have returned the favor and said, "What? You must be joking..." because it reset the FSB back to 133.There doesn't appear to be anything in this BIOS for AGP/PCI freq. locking or even the ability to change the clock dividers.*sigh*J

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