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We get a lot of emails each day and we try to answer each one. You can help us in this task by first reading the FAQs below:

Q: How do I overclock an AMD system?

A: Please read "AMDFAQ" – this covers most questions related to AMD’s CPUs and systems.

Q: My AMD CPU runs at 40/50/60C – is this too hot?

A: Please read "AMD CPUs: How Hot Is Too Hot?"

Q: How do I overclock?

A: First read the article "Overclocking FAQ" by Frank Monroe – it answers many of the basics and is required reading for first timers. Another article with excellent details is on CPU Site. Once armed with the basics, check the other sites listed in Cool Links for further tips and overclocking articles. This is how I got started and it works.

Q: But what about my ABIT Motherboard?

A: Mark Dressel wrote the “General Celeron 300a Overclocking Guide for ABIT Boards:

Boot Up and hit DEL to go into the BIOS;

Go to the top setting for CPU Soft Menu;

Toggle through CPU Soft Menu until you get it to say “User Defined”;
Set the CPU Bus Speed to 100 MHz;

Set the CPU Multiplier to 4.5this can never change as it is locked!;

(If you have an AGP video card) set the AGP Clk Set to 2/3 (probably default settings show 1/1 – NEVER RUN AT 1/1 when overclocked);

Go to the CPU voltage at the bottom and set it to CPU Default 2.0;

Now ESC back to the Main Menu page in the BIOS;

Toggle all the way down to the PCI/PNP Config menu;

The first setting is called Force ESCD – set this to ENABLED;
You have to do this EVERY TIME you make a BIOS change!

Now, before you start – move your memory DIMMS over to bank 3 – work
backwards – fill bank 3 first – if you have more memory then fill bank2, then bank 1 last if necessary. The best is using 1 DIMM in bank 3.

Now reboot and you should post at 450Mhz!! Aim to run it at 2.0 volts; If you lock or crash then up to 2.1 and try again, then 2.2 and try it again!!

Remember – voltage increases creates heat – heat will lock the CPU – the lower the voltage the better you will be!!

Q: How do I identify my chip? How do I tell the week? The plant? Retail or OEM? Klamath or Deschutes?

A: The Pentium II has a series of numbers on top of the chip stenciled in white; the Celeron has these numbers on the back of the chip. The important codes are the “S” Codes and the FPO/BATCH#s. The “S” Code looks like “SL2WY” – it identifies what chip this is and which variation; Go to Cool Links p. 3 for Pentium and Celeron “S” Code Tables. From this Intel Table you will be able to find out your CPU’s basic configuration.

The FPO/BATCH# looks like “08310527-0411” for the Pentium and “08310527” for the Celeron. The first 4 digits (0831) give you where it was made (0=Costa Rica, 1=Philippines, 9=Malaysia, Y=Ireland), year made (8=1998), and the week it was made (31=week 31). The CPU Database displays performance data identified by these codes. The rest of the numbers are serial #s to identify from which batch the chip came.

Q: What can I expect from overclocking my chip?

A: The most popular overclocked chips are:

C300a to 450 @ 2.0-2.3v @ 100 MHz bus, codes SL32A and SL2WM
PII300 to 450 @ 2.0v @ 100 MHz bus – codes SL2W8 and SL2YK
PII333 to 500 @ 2.0v @ 100 MHz bus – codes SL2WY and SL2TV

Many of these chips are capable of running even faster at 112 MHz bus speed. Other Pentium IIs and Celerons that run on 2.0 volts may be capable of overclocking by changing the bus speed from 66 MHz to 100 MHz; for PIIs, the cache speed is usually the limiting factor. Unfortunately other than the CPUs listed above, overclocking other PIIs does not lead to the consistent results listed above.

PII350s and above run at 100 MHz so overclocking these requires you to run at bus speeds where ram becomes very critical. All Intel CPUs made after August 1998 are multiplier locked, which means that you can only change the bus speed, not the CPU’s multiplier.

Q: I have a PIIxxx or Celeron xxx – can I overclock it?

A: Any chip can go 10-20% over its spec rating. The key question for PIIs is which version – Go to Cool Links p. 3 for Pentium and Celeron “S” Codes. If your Pentium is 2.8 volts, the overclocking potential is limited. If it’s a Celeron made in Costa Rica, most likely you will have to increase voltage to make it stable at its overclocked speed. Any questions to us must include your “S” Code and FPO/BATCH # of the chip. Pentium codes are on top of the chip’s case in stenciled white letters; Celerons are found on the back of the chip in a white square.

Q: But what about the Celeron 333a?

A: Not a bad choice but not like getting the 300a to 450. The Celeron CPUs start to “hit the wall” at about 500 – this is why it is realtively easy to get to 450 with the 300a but harder to get to 504. I figure the odds are about 20-40% that you will make the jump to 500. If you don’t, then you have 415 – not as good a choice as the 300a to 450.

Q: But what about plain old Pentiums?

A: There is a great Pentium Overclocking article on Toms Hardware and another one on which covers the “older” CPUs – nothing wrong with wringing a little bit more out of these.

Q: What is the basic method used to overclock?

A: Since Intel’s chips since August 1998 are multiplier locked, the only alternative is to increase the bus speed on the motherboard to run the chip faster. For example, the Celeron 300a achieves 300 by running 4.5 x 66 MHz bus speed. If the bus speed is changed to 100 MHz, it is now running at 4.5 x 100 or 450 MHz. This is possible because Intel basically makes all its chips the same way – the best ones are sold as PII450s, then PII350s, etc. However, Intel is so good at making chips that many of those marketed as lower speed CPUs are in fact capable of running at higher speeds. NOTE THAT if you damage your chip by overclocking, Intel will not honor your warranty.

Q: I have a Gateway (or Dell, IBM, Compaq etc) computer and want to overclock it. How do I do it?

A: Basically you can’t. These are all good machines but the motherboards are very narrowly designed to work within the range of the installed chip. Usually jumpers are not available or limited such that there is not enough flexibility to adjust multipliers, bus speeds or voltages to accommodate overclocking.

Q: I don’t see the code for my chip in the CPU Database – why not and will it overclock?

A: We don’t have every chip listed – we rely on user inputs for the CPU Database. However, what you can see from this data are clear trends: For example, Malaysian Celerons tend to overclock better and at lower voltages than Costa Rican chips. Certain weeks are better than others – For example, Week 37 PII333s overwhelmingly hit 500 at 2.0 volts. We strive to report and identify emerging trends based on these samples.

Q: I tried to overclock my CPU and it won’t work – What can I do?

A: There are four primary areas to check:

1. RAM – I would say 80% of the time RAM is the issue. If you are mixing RAM types or have PC66 with PC100, you are set for trouble – sometimes it works great, sometimes not. Just because it says PC100 does not mean it is stable in overclocked systems. Generic PC100 will sometimes work and sometimes not – you can slow down the CAS ratings in the BIOS to 3 to see if this helps. On ABIT boards try putting the RAM in the 3rd DIMM slot. As a further test, borrow a friend’s RAM and try that in your system. Best RAM I have found is SAMSUNG GH or even better G8.

2. Cooling – If the chip feels hot or your system temperature is more than ten degrees over room temp, cooling may be the problem. Open the case, aim a house fan at the motherboard and try again. If you are OK, then cooling is the problem. Look in Articles for cooling tips.

3. Voltage – If you have not upped voltage, try this next. Many CPUs will require a voltage boost to make the overclocking jump. If you don’t have an ABIT motherboard, you will have to tape pins to do this – Go to Cool Links p 4 for “Taping Pins for Voltage Changes”.

4. Video Cards – Many run hot when overclocked and will prevent you from reaching your goal. Feel the video chip – if it is really hot, then cool it down per item 1.

Q: I bought a Pentium xxx of Celeron xxx, tried all the tips and it still does not work – Why?

A: There are no guarantees in overclocking – all we can do is help you increase the odds of success by using the data we collect. CPUs follow the normal curve – a small percentage of Celerons 300a’s will overclock to 558 at 2.0 volts and a small percentage will not overclock at all – most will fall in the middle and overclock to 450 at 2.1 volts. The only way to get a guarantee is to buy a pre-tested chip; usually you will pay a premium.

Email CPU comments, suggestions, and questions to Joe Citarella

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