|Celeron PPGA overclocking / overbussing / FAQ|
Celerons come in different variations. I.e: the C266 and C300 without L2 cache and the the rest with 128 Kb L2 cache. Each type of Celeron has several slightly different variations, called a "stepping".Stepping 0 (zero) cores are the original production run. When minor imperfections (bugs) are found in the instruction programming (micro-code) of the core or in other parameters of the chip, they are fixed and the next batch of cores will incorporate the changes. This batch will be identified as stepping 1. If another change is required later, the stepping number will be incremented again. As each successive refinement to the chip is made, the next higher stepping number will be assigned. For many reasons, one stepping may be easier to overclock than another, but usually the higher stepping cores make the best, most stable CPU's. From 366Mhz and upwards Celerons started to use a new slot - s-370 .. and from 400Mhz you can only get celerons using s-370 whilst the 300Mhz and 366Mhz can be obtained using both s-370 and slot1..If you want to use a s-370 in a slot1 MoBo you need a slot converter /slotket - there are several brands to choose from.
An S-code (Intel actually calls it an S-Spec.) is a 5 character designation beginning with 'S' used to identify the various different types, stepping, voltage and packaging of Celerons and other Intel processors. OEM packaging is in a plastic container. There is no heatsink/fan attached, so you need to buy your own.
The retail Celeron (also called a "boxed" Celeron) comes in a cardboard box with a heatsink and fan already attached. You also get a Certificate of Authenticity and an installation notes booklet , a cute sticker for the front of your computer and a three year warranty from Intel. The S-code can be found on one end of the retail box or on the back, left side of any Celeron printed circuit board. For detailed informations download datasheets HERE ( .pdf format Adobes acrobat reader needed - get it here.)
NOTE : all celerons are listed in this table
Multiplier and buslocking
Overclocking a Celeron is impossible ; You actually overbuss it to achieve higher cpuspeed.
All Celerons are multiplier locked.
C300 is multiplier locked at 4,5
C366 is multiplier locked at 5,5
C400 is multiplier locked at 6.0
C433 is multiplier locked at 6,5
C466 is multiplier locked at 7,0
C500 is multiplier locked at 7,5
No Celerons are buslocked
Celeron ppga's are all intended to run at 66 MHz bus speed !
Q : Can I disable the multiplier lock ? A : No one has been able to do this so far J
@ You are lucky if you get up to this level - higher buses might require additional / improved cooling. Celeron's can go much higher than stated in this table with exotic cooling. The trend is that the processors are getting harder to overclock the higher core frequencies they come in.Do this indicate that the core has meet it's limits and has no more to give ? Note : there are motherboards with more/different multipliers than mentioned here !
Which motherboard ?
Motherboards of choice for overclocking a Celeron, is growing everyday. The Abit BH6 is still one of the most popular MoBo's with owners of the Celerons for a couple of reasons. First, this motherboard doesn't need a BIOS upgrade to recognize the Celerons. Secondly, it allows you to increase the CPU voltage from the BIOS SoftMenu. This feature is particularly attractive since many Celerons need a voltage higher than the default setting of 2.0 volts to be completely stable. Additional features that make the BH6 popular are its low cost and BIOS SoftMenu setup for all settings you need to overclock. We used a Abit BX6r2 when we tested overclock abilities on the s-370 Celerons This particular motherboard have been running at 153MHz FSB with a PIII450...
If you have a slot1 motherboard you will need a CPU converter board there are several brands out there...We had the choice off two and frankly we did not notice any "huge difference" .. But we were very impressed with the MSI MS-6905 (can also be used for dual mode) - This was a product made for the overclocker with jumper settings on the converter board from 1.8Volt and all the way up to 2.6Volt.. Also had jumpers for single/dual CPU mode and a overclocking (!) jumper which "virtually set 66MHz to 100MHz"..... But our favourite is the extreme stable Asus 370-D - used in Asus P3B-F and with the 1003 bios it can boost CPU voltage to 3.2Volt !!!! Voltages above 2.3 is not recommended if you don't have a extreme peltier solution or a VapoChill.
tips for first time overclocking :
Too much too handle ?
If you feel that you still don't understand how to crank up your Celeron ,and feel insecure how to do it - just leave it as it is. The Celeron is still a good performer taking in concern the price / performance ratio . If you really want to crank it up anyway - get someone to help you with it. In the download section you'll find a utility that let you change the bus speed from your desktop ! It's always a chance that you destroy something when you push your system to the edge ; that's the price of overclocking. Visit the windows section too - these tip's and tricks will give you more performance too.
One of our results :
Celeron400MHz SL37X Malay - 100% stable at 630MHz / 2.3Volts / L2 set to 1 ( L2 explained / revealed here ) with OcShoot's peltiers ! For more overclocking results check out the VapoChill section ! Off course the core is lapped in to ensure as good heattransfer as possible. (how to lap the slug / core here ) And we used the best thermal paste available on the market.