Overclocking the Celeron 566 on Asus CUBX

(3 weeks of research summed up in 3 minutes reading)

Updated 7/06/00

6/02/00            Install OEM Celeron 566 in Asus CUBX Bios Ver 1005 using generic Heat sink/fan provided by CPU vendor, Bios fails to recognize CPU, no jumper settings available on the Asus site. Manually set dip switches for 8x 66 MHz, motherboard identifies CPU correctly as Celeron 566. Don’t want to trash my primary drive, so take an empty hard drive, and attempt a fresh install of Win 98. Two tries with no success. Remove all cards except SVGA. Install fails half way through each time. Maybe the drive is not compatible? Install an old drive with a Win 98 Ver 1 installation already on it. Win 98 detects the new HW and I am up and running. CPU is running extremely hot. Intermittent warning tone from motherboard.

6/03/00            Go to Radio Shack for Heat sink compound. Temp drops 30 degrees after application. Install 2 more case fans in my Acer full tower. The tower now has 6 fans:

1)       CPU                                                             2)  power supply

3)  provided mount, lower front                           4)  1st provided mount, upper rear

5)  2nd provided mount, upper rear                     6)  custom mount fan directly above CPU and chipset

I sure hope this solves my temperature problems!

6/04/00            Seems to be running stable and cooler now, around 30 degrees C. Lets try to overclock it.    8.5 X 75 for 637 MHz is ok, as is 8.5 X 83 for 708 MHz. But can’t go higher. Remove all cards (NIC, Sound, SCSI, and Modem)   from the computer except my ATI all in wonder AGP. Still no go. Try a PCI SVGA no good either.  I have no way to adjust my voltage with the jumpers. How come Asus says this board can support Celeron 566 but the Bios will not recognize the chip? Their technical reference page refers to Bios version 1006.001, but where the heck is it? E-mail Asus support, post to the Asus news group, and check Asus NetQ. I see why they call it NetQ it is definitely just like a waiting in a Que. I think they must be running NetQ on a 386.

6/08/00            Asus never replies, but someone in the news groups says “ Try Asus Germany they always have the latest Bios.” Go to Asus Germany – Sure enough there it is: beta Bios 1006.003. Install the Bios and Voila – the CPU is recognized as a Celeron 566. Lets try to over clock again. Now I can run at 875 MHz at 1.65 V. Lets start putting cards back in one by one. Well all the cards are back in and I can still run at 850 MHz. I am only using pc100 memory so wasn’t expecting much more. I am having some warm boot / reboot problems, but everything always comes back up if I turn the power off. A small price to pay for an extra 284 MHz, and hopefully the next Bios rev will fix the problem. Overall I am very pleased.

6/09/00            Better post my find to NetQ for any other poor souls waiting for a response from Asus.

6/10/00            I have been getting some really bizarre readings from Asus probe. My 12V 5V and 3.5V will sometimes suddenly drop by 50%. Could be my power supply is going out, better try another. Replace power supply.

6/11/00            Still bizarre probe voltage readings. Put the original 300W Acer back in. What is going on here do I have a bad board?

6/13/00            After a couple days of fiddling around I realize it is the crappy Asus Probe software causing the problem. Disable “Smart Fan Control” and the problem goes away. Later I notice many posts from people who have this same problem with a variety of Asus boards when using Asus “Dumb Probe”.

6/14/00             Now that I have my original hard drive back in the Computer running 98SE I want to utilize the CMD UDMA 66 controller. I put my UDMA Quantum on the channel and run some benchmarks. What gives I am running much slower on the UDMA channel. Set the board back to 566MHz and try various settings, also I do a hardware redetect, some devices are updated but things are still slow. Manually override the CMD setting and set to UDMA mode 4, now I am moving. HD tack shows 58MB burst. The driver does however have a negative impact on boot time. It takes and extra 30 seconds more with the CMD controller.

 6/15/00            Now that I have the UDMA going lets go back to 850MHz. – Ah Oh! – no go! now I am locking up at the windows desktop every time. Only safe mode works at 850MHz. Well I suppose if I have to pick between 566MHz and UDMA 66 or 850Mhz and UDMA 33, I will pick the latter, my drive can’t sustain 66MB anyway. Put the drive back on the BX IDE channel … No Way! now I can’t run on that channel at 850MHz either. What happened?! I reset the CPU to 566 then go in and turn off DMA on the hard drive and reboot at 850 – No good. Next I run MSCONFIG and set the hard drive to compatibility mode and reboot at 850- still no good. I am beginning to get irritated. OK .Set the CPU back to 566Mhz, I do have a life besides working on this @#$%&^* motherboard! 

6/17/00             Have some time today so its back to the workbench, remove all the cards except the svga. Still no luck at 850Mhz. Run system file checker – still no luck, Go to device manager and remove all mother board devices and the redetect – still no luck, re-install Win 98 still no luck. I can’t believe it I have been working on this for almost two weeks and I am back to square 1. The Board simply will not over clock except in safe mode. What the heck happened I had 850 MHz! 

6/20/00             Ok if I can get in safe mode it must be some kind of driver problem. Where is that old spare drive with Win 98 Ver 1? I install the drive and right away - Bang .. 850Mhz. Ok what gives? Is it the version of windows? I don’t think so since I was able at one time to run 850MHz with Win98SE.  

6/22/00             I print out a copy of my system devices settings. (Alt-print screen, then paste to paint brush) And sift through item by item. I notice that on My 98SE installation the Bios is called ACPI Bios, and on my 98 Ver1 installation it is called Plug and play Bios (should be plug and pray!) maybe I am on to something! Back up the registry. Remove the ACPI Bios and re-boot. Ok that got rid of the Bios but all my other devices as well. If I do a redetect it will put the ACPI Bios back as well as the other devices. Restore the registry. Reboot. Select ACPI Bios and update driver. Now I select Plug and Play Bios (fail safe). Reboot. Everything seems OK at 566. Reboot at 850. I am holding my breath as I reach the desktop.......... Oh my Gosh I am back to running at 850Mhz again.

6/23/00            Run a variety of test / burn in programs.. no crashes. System is rock stable running 850 MHz with 1.6V @ 45 Degrees C. The Fail safe bios has not hurt performance at all, actually I am running slightly faster on some benchmarks. Although I have not needed it, there still seems to be a problem running the Celeron at any voltage higher than 1.65 with the current board / Bios.

6/25/00            Running stable for 3 days now: No more reboot/warm boot problems either. I am proud of my accomplishment. I have spent 3 weeks of my time combing the Asus Support site, news groups, and  NetQ, flashing Bios, and re-booting, changing Bios settings and re-booting, changing Win98 settings and re-booting, removing software, and re-booting, reinstalling software, and re-booting, removing hardware, and re-booting, putting the hardware back in, and re-booting, switching hard drives and re-booting, switching hard drives back and re-booting.

But ….I HAVE MADE MY CPU PERFORM ON THE LEVEL OF ONE PRICED $100 MORE!!!! (Sarcastic tone intended)

What happened to the good old days when cases had digital LED's so you could just change the number and say you were running that fast???




Well I violated one of my rules today, which says " If it ain't broken then don’t fix it". Though I have been running Rock solid at 850 MHz for some time now, I was curios to see if the new bios Ver 1006.004 would address two issues: 1) the Celeron voltage problem 2) The need to use PNP(fail safe) device drivers instead of the normal ACPI Bios Drivers. Since the brilliant team at Asus does not see fit to release any info whatsoever regarding Bios updates, the only way to find out is to give it a try.

1)       Put everything back to 566 MHz

2)        Flash the Bios

3)       Return to 850Mhz … All is well.

4)       Attempt to boot at any voltage over 1.65... still no good.

5)        Uninstall the PnP Bios device drivers and re-install the correct ACPI drivers ... Still cannot overclock with the ACPI drivers. I lock up at the 98 desktop every time

6)        Recover registry ... all is stable again at 850MHz with the PNP driver.

Conclusion - I just wasted 45 minutes, the new Bios has not addressed any of the issues I am experiencing. If you are stable with the PNP driver don’t waste your time.

Click here for The CUBX BIOS Ver 1007.004 check sum = 0296

Click here for The Win 98 CMD 648 IDE Driver Ver 3.1.5

Click here for The Win 2k CMD 648 IDE Driver Ver 2.0.4

Click here for The Win NT CMD 648 IDE Driver Ver 3.0.8

Click here to for a picture of  my system devices

Click here for my system configuration

Click here for Answers to some CUBX questions

Hot! Click here for some answers to important questions of eternal value Hot!

New Click here for a comparison of 4 FC-PGA fans that fit the CUBX New

Other CUBX sites:

cubx info and downloads page

Asus CUBX MoBo World!

Feel free to link to this page, but I would appreciate a note letting me know where the traffic is coming from.



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