overclocking FAQ

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hopefully this can be a useful resource for those of you having trouble overclocking.

Disclaimer: this is not a complete guide and should be used in conjunction with prior knowledge or other guides. this is only to serve as quick reference so don't blame anyone if your parts get fried.

Q: How can i check that my overclock is stable?
A: One of the best ways is to run a demanding test like prime95 over a long period of time. run the "torture test", this will stress your processor and if it returns errors then you know the overclock is unstable. (for dual cores see below)
Caution: this will probably significantly heat up your processor so keep an eye on temperatures.


Q: How can i test the stability of my dual core?
A: Once again this can be done with prime 95. however to truly test the stability the program has to be run on each core. to do this open the program and also find out where it is located e.g C:\program files\prime95\prime95.exe. take not of this in type into the run option in start menu ["C:\program files\prime95\prime95.exe" -A1] without the brackets but including the quote marks, of course change the C:\ etc to wherever prime95 is stored on your computer. in the program click advanced>affinity. set one to cpu 0 and the other to cpu 1 and run a torture test on each. also i have noticed that there seems to be some trouble running blend on dual cores as one core runs at 100% and the other is barely used. my way around this is to use custom and specify a number in MB that is less than half your system memory. i use 300mb on each instance.


Q: How can i test the stability of my overclocked memory?
A: memtest86 is a great program for testing memory. just download it and make a boot cd. keep in mind to let it run through at least 3 passes


Q: I think my processor is unstable what can i do?
A: increase the processor voltage (vcore) very slightly and see if that improves its stability. keep in mind increasing the voltage will increase its temperature. if all else fails back down the overclock a little


Q: I think my memory is unstable what can i do?
A: increase the memory voltage slightly (vdimm). this will void the warranty on most memory though and many manufacturers will reccomend you don't exceed 2.85v. you can "loosen" the memory timings. another thing is to use a "memory divider". a divider lowers the ratio of the memory speed to the processors FSB speed. for example the standard is 1:1 so your processor FSB at 200mhz will give you a memory speed of 200mhz (DDR400). if you were to use a memory divider in this case of say 1:2 then the memory speed would be half that of the FSB i.e. 100mhz (DDR200)


Q: My overclocked pentium 4 boots fast but after a while slows down, why is that?
A: there is a good chance that the processor is overheating and in the case of pentium 4's the performance of the processor is reduced to protect it from damage. get a better cpu cooler or take the overclock back a bit.


Q: When i overclock i get BSOD's sometimes even before windows has booted. what is causing it?
A: whoa slow down!!! you've probably overclocked too far. there is a good chance the errors are coming from your memory so use memtest86 to check for errors. once again if all else fails reduce the overclock.


Q: I have overclocked my processor quite a lot but i had to reduce my memory speed to allow it, but now it performs worse than before. whats going on?
A: Overclocking can be a lot about compromises, sometimes higher clock speeds don't necessarily give you better performance if you have to for instance reduce memory speed or latencies. you have to find the best balance of speed and memory bandwidth.


Q: I just built my new computer when should i start overclocking?
A: Dont start overclocking immediately, if you applied some AS5, it will take a couple of days for it to set it, and you want to wait for your sillicon to expand. Usually the expanding of the silicon and letting the AS5 settle in will lower your temps and let you overclock a little more.

Q: I have a Sony VAIO computer/Dell computer/HP computer/ Gateway Computer/ Any prebuilt computer can i overclock it?
A: No, any prebuilt computer usually locks their bios so you can not change the FSB/HTT or any other thing. The only way to overclock is if you use Clockgen, which is overclocking through windows. Or you can flash your bios with one directly from the mobo's manufacture's website. Or for a last choice, you can buy a new mobo which has everything unlocked

Q: What are RAM timings?
A: RAM timings are the 2-2-2-5 and the 3-4-4-8 that the veterans talk about when it comes to RAM. Now what are these numbers really? They actually refer to the delay timings of a certain stick of RAM. Less delays mean faster RAM. Simply put, the lower or tighter the timings/delays, the faster the RAM is. Meaning 2-2-2-5 is faster than 3-4-4-8 assuming that the clockspeed of the RAM remains the same, and only timings are different.

When someone refers to RAM timings as 2-3-4-5, they usually mean, from 1st number to the last number:

1. 2- CAS latency time
2. 3- RAS# to CAS# delay
3. 4- RAS# Precharge
4. 5- Act to Precharge Delay

Not all RAM can run at the tightest/best timing of 2-2-2-5. Generally, high-quality lower speed RAM like DDR400 will have tighter timings, while most DDR500 RAM will have more loose/relaxed timings (usually 3-4-4-8).


Q: What is a memory divider?
A: A ram divider is usually a setting found in your ram tweaking setting menu in your BIOS. One popular way of overclocking your processor is to increase your FSB/HTT. This increases the processor speed, and memory speed equally. In the event that your processor still has the ability to increase in speed, but your memory is maxed out, you would use a memory divider to slow down your memory. Example: You want to run your FSB/HTT at 200Mhz, but your memory maxes at 100Mhz. Set the FSB to 200Mhz, and a memory divider of 1:2, and the memory will run at 100Mhz. Common dividers include 1:1(200), 9:10(180), 5:6(166), 1:2(100)

Q: What is HTT?
A: The HTT is the speed at which the cpu communicates with the motherboard. This is different than a traditional Front Side Bus (FSB) because on A64's there is no northbridge. The northbridge was the memory to cpu communication point on pentiums. A64's now have that memory to cpu communication point integrated into the cpu itself, so the FSB doesn't exist for them. Instead they use the term HTT which functions as the A64's FSB equivalent for OCing purposes.

Q: What is burning in?
A: Burning in is a process of a) breaking in your processor and b) forcing your processor to operate stable at a lower voltage than before. e.g an overclock that is only stable at 1.375v and forcing the processor to operate at 1.35v until it is stable. it is a difficult process and some extra research is necessary to do it properly.

Q: I overclocked my computer but how do i know if it's working?
A: You should download CPU-Z Click Here and it will tell you all you need to know about your CPU and mobo

Q. I overclocked my AMD processor, how do I know what my Pentium rating is now?
A: Download Central Brain Indentifier.
Click Here
It will tell you how your AMD compares to a Pentium 4 and many other things.


Q: What if my in windows temperature monitor is showing a high temperature?
A: Before you do anything, check BIOS, in windows temperature monitors arent the most reliable, if the BIOS says the temp is above 60C reduce the overclock or get a better heatsink/fan, but reduce overclock till that arrives. its good to keep an eye on how much the windows reading differs from the bios reading so that you can guage roughly what the true temperature is in windows.

Q: How can i find out if my RAM is holding back my overclock?
A: Use a high memory divider like 1:2 to keep your ram from overclocking and push your cpu as far as it will go.

Q: How can i get some sort of an indication of the performance boost i have gotten out of an overclock?
A: You can use programs such as superpi to run a "benchmark" test on your pc. in other words to give you some numbers to judge performance by. with superpi run the program to calculate 32m before your overclock and record the time. do the same thing after and the time difference can be used to show how much performance has improved. another good way is to use SiSandra's CPU benchmark. this will give you a performance rating. also there is PcMark

Hints:
#1, most important: FOR THE LOVE OF GOD READ THE OVERCLOCKING GUIDES AND DO SOME RESEARCH!!!!!!!!!

always take things slowly and in small steps

NEVER overclock quickly and assume its stable and continue using your computer as you normally would. make sure that it is STABLE and keep an eye on temperatures before you do anything like gaming. you might get a nasty surprise if you don't do this.

AS5 (arctic silver 5) is a good way to significantly reduce processor temps

if your computer is not in perfect working order don't overclock. get everything sorted out first otherwise it can make diagnosing the source of problems annoyingly difficult.

A good way to find the overclocking ability of your cpu is to use a high memory divider so that your ram will not be overclocked at all, this way you can determine that your cpu is causing instability rather than your RAM

Thanks to PZEROFGH, Flying-Squirrel, OpticalIllusion and The_Tobes99 for their contributions
 
Q: I just built my new computer when should i start overclocking?
A: Dont start overclocking immediately, if you applied some AS5, it will take a couple of days for it to set it, and you want to wait for your sillicon to expand. Usually the expanding of the silicon and letting the AS5 settle in will lower your temps and let you overclock a little more.

Q: I have a Sony VAIO computer/Dell computer/HP computer/ Gateway Computer/ Any prebuilt computer :) can i overclock it?
A: No, any prebuilt computer usually locks their bios so you can not change the FSB/HTT or any other thing. The only way to overclock is if you use Clockgen, which is overclocking through windows. Or you can flash your bios with one directly from the mobo's manufacture's website. Or for a last choice, you can buy a new mobo which has everything unlocked :D
 
Q: I overclocked my computer but how do i know if it's working?
You should download CPU-ZClick here and it will tell you all you need to know about your CPU and mobo :)
 
I wish the person who did the original post could remove replies after he updates the FAQ. :(

A mod should take care of that for us :D
 
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