underclocking a celeron 1200 tualatin

tridion · Post by **tridion** » Sun Dec 15, 2002 4:33 am

I bought a Jetway BN860T motherboard and a Celeron 1200 tualatin. Te motherboard box stated that the FSB could be set to 66mhz and that the voltage could be changed.

I thought I would be able to succesfully underclock the Cereron and hopefully run it fanless.

However in the BIOS, I dont seem to be able to drop the FSB below 100 and there doesnt seem to be any voltage option.

There doesnt seem to be a BIOS update on their web page and changing the MB isnt an option. Does anyone know how I can at least drop the FSB to 66.

BTW - even at 100mhz the cpu is running fanless although the case is open and I think it will overheat if I close it.

Post by **Ralf Hutter** » Sun Dec 15, 2002 2:41 pm

Look at my rig specs below.

I'm running an OCed 1.1A @ 1.475Ghz on default voltage. I'm using a Thermalright SLK-800 and a 7-volted Panaflo M1A fan. This runs 45-46C at full Prime95load and is damn near dead silent. You can't even hear the HS fan from more than 6-8" away.

Prior to this I was running at stock speed with the retail Intel HSF 7-volted. It was just as quiet but temps were in the low 50C range at load.

I suggest leaving your 1.2A at default speed (100FSB) and run the retail fan at 7-volts. Unless you live in the middle of the desert with no AC that setup should keep your CPU plenty cool and be nearly inaudible.

tridion · Post by **tridion** » Mon Dec 16, 2002 3:15 am

Thanks for your reply. However this is not an option because :

1. I have already tried the SLK-800 and it doesnt fit inside the case (case is to slim.
2. You cant fit a fan on top of any heatsink (expect very short ones) because of same reason as above.

These cases (Cubid 2688R) are really intended for Via Epia boards and via c3 cpus but thought I would get away with it if I could run the celeron without the need for a fan.

tridion · Post by **tridion** » Mon Dec 16, 2002 5:04 am

Well, I am giving up (for now) on running this celeron at 66 FSB.

I have a Via C3 933 chip lying around which is also compatible with this MB. However, while running this machine with the celeron 1200 at 100FSB (i.e. normal speed), DVD playback was disappointing. I am running PowerDVD software decoder (this machine has no hw decoder) and playback is ok when nothing else is running but if any other process kicks in in the background, playback starts stuttering. Even with nothing else running, playback doesnt seem as smooth as it should be.

I am surprised by this - I would have thought that a celeron 1200 would be ample to deal with dvd playback in software.

This worries me if I use the via c3 933. This has nowhere near the processing power of the celeron so how is this going to fare ? Surely it is going to struggle big time.

I could add a pci video card (there is one pci slot) and was thinking of the ATI All-In-Wonder. Would this solve the problem ? Would I get good DVD playback even with a C3 933 cpu ? What about Divx ?

I was thinking of the Sigma XCard but apparently its Divx support is flaky.

gksam · Post by **gksam** » Tue Dec 17, 2002 2:21 am

I am quite surprised by that. My Celeron 300A (at 4.5*66 = 300mhz) a few years ago could hardly muster DVD playback without any hardware acceleration (using powerdvd or windvd). CPU would be at 80-90% utilization.

However, my P3-450 laptop could handle it flawlessly...

so I'm thinking something is the issue. Did you enable DMA mode on your DVD drive? this makes a HUGE difference. You might have to install some IDE busmaster controllers depending on what chipset you're using.

tridion wrote: I am surprised by this - I would have thought that a celeron 1200 would be ample to deal with dvd playback in software.

tridion · Post by **tridion** » Tue Dec 17, 2002 4:59 am

Thanks for that, but how do I enable DMA ?

Also what is an IDE busmaster controller and how do I install it ? If it is hardware then I doubt I can as I dont have a spare PCI slot.

Post by **Ralf Hutter** » Tue Dec 17, 2002 6:06 pm

tridion wrote:Thanks for that, but how do I enable DMA ?

Also what is an IDE busmaster controller and how do I install it ? If it is hardware then I doubt I can as I dont have a spare PCI slot.

DMA stands for Direct Memory Access. It's a software setting and how to enable it depends on your OS. What OS are you running?

A busmaster controller contols the transfer of data on the IDEchannels. These drivers are usually included in the OS but newer, better versions are usually available from motherboard manufacturers for the various chipsets (Via, Intel etc)

gksam · Post by **gksam** » Wed Dec 18, 2002 12:49 am

I'm sorry, I meant to install busmaster drivers (as Ralf was talking about).

Go to your chipset manufacturer's website for the drivers for your chipset. Usually they enable DMA by default after installing them.. otherwise you have to manually do it -- and it depends on what OS you are running as Ralf also mentioned.

tridion wrote:Thanks for that, but how do I enable DMA ?

Also what is an IDE busmaster controller and how do I install it ? If it is hardware then I doubt I can as I dont have a spare PCI slot.

tridion · Post by **tridion** » Wed Dec 18, 2002 1:50 pm

I'm running WinXP. I have a motherboard based on the Via PLE133 chipset (I think) now running a Via C3 933 cpu.

DVD playback is about the same as it was when there was a celeron 1200 in it (which I find strange).

Anyway, how to check if DMA is enabled in WinXP ?

Post by **Ralf Hutter** » Thu Dec 19, 2002 5:16 am

tridion wrote:Anyway, how to check if DMA is enabled in WinXP ?

Go to "System Properties(right-click on "My Computer", or go to "Start>Settings>Control Panel>System"), then go to "Hardware>Device Manager" then click on the "+" next to "IDE ATA/ATAPI controllers". You will see both of your IDE channels there. The Primary IDE channel is where your HDD should be mounted, the Secondary channel is (usually) where your optical drives should be mounted. Double-click on either one and go to the "Advanced Settings" tab. It will show both devices (if they're there) on the IDE channel. "Device 0" is the Master and "Device 1" is the slave. Look at the box that says "Current Transfer Mode". If it doesn't say something about DMA in it, go to the "Transfer Mode" box. This is where you can enable DMA if required. Notice that you can choose between "PIO only" or "DMA if available". Select "DMA if available". Do the same thing all devices on each channel, repeat on the other IDE channel, then "OK" out.

Now you should have DMA enabled on all your IDE devices. Don't be scared, it's easier done than said. You'll see.