Due to a recent spike in "how do I overclock my CPU"-threads, I decided to write this, so that I can just paste a link (or refer to a sticky ), instead of re-typing the basics of overclocking every time. In this thread, I'll go through the mentioned basics. It is mainly for Intel-based machines, but the same things apply to AMD, it's usually just other words.
A VERY LARGE MAJORITY OF OEM (Dell, Acer, Fujitsu-Siemens, etc) BIOSES ARE LOCKED, AND HAVE NO OVERCLOCKING OPTIONS. IT IS GENERALLY IMPOSSIBLE TO OVERCLOCK THE CPU IN AN OEM MACHINE.
OVERCLOCKING CAN VOID YOUR WARRANTY. INTEL CAN TRACE IT IF YOU PUMP 1.7V INTO YOUR BRAND NEW 45NM CPU. OVERCLOCK ON YOUR OWN RISK!
(The real risk of damaging anything, if you do it right, is, however, really slim.)
Terminology
You won't need most of this, but it's good to know, and I don't want an excessive number of Xfire adds.
Term (Other popular names) - Description
VCore (Also called: CPU voltage, CPU VID (rare), Core voltage) - it's the main voltage of your processor. The higher, the higher clocks you can reach. Going too high will make your CPU degrade over time.
FSB (Usually just called FSB, short for Front Side Bus) - It's the speed of the bus your processor is on. Raising this will raise the processor's speed, and it's the main thing used when overclocking a processor.
Multiplier (Also called: Multi, x, FSB multiplier) - The number of times your FSB is multiplied to create the final CPU speed. A multiplier of 10x on a 266MHz bus equals a 2.66GHz CPU. Can generally only be changed to a lower value.
RAM multiplier (Also called: RAM Divider) - The number of times the FSB (not quad-pumped) is taken to create the RAM speed. A 200MHz FSB with a RAM multiplier of 2 makes for 400MHz RAM. Most RAM is a variant of DDR, which basically means that the RAM has double the effective speed of the bus it's on. 200MHz DDR equals 400MHz effective. DDR800 (PC6400) is really 400MHz, but due to it being DDR, it's 800MHz. A RAM divider of 1:1 (Often called 2.0 on Intel chipsets) means that the RAM runs at the same speed as the FSB.
Quad-pumping (Not called anything else) - A technology used to improve bandwidth on buses. A single-pumped bus signals once every top of the pulse. A double-pumped signals on every top and bottom, and a quad-pumped signals every top, bottom and middle. A quad-pumped bus of 266Mhz equals 1066MHz effective. The final frequency of the CPU is, however, counted from the single-pumped speed.
Northbridge (Also called: MCH, NB) - The chip that connects all the buses in your computer, PCI-E, FSB, etc. It often requires more voltage to reach high FSB speeds. In some cases, it might even need additional cooling.
PCI-E bus (Also called: PCI-E frequency) - the bus that your graphics card, and possible other PCI-E devices lie on. This should remain at 100MHz all the time, and is generally not a concern when overclocking.
RAM voltage (Also called: DDR voltage, memory voltage, vMEM/Vmem) - The voltage of your RAM. It might be neccesary to raise, if you've reached an FSB speed higher than the speed of your RAM, as many chipsets won't let you choose RAM:FSB ratios lower than 1:1.
VTT (Also called: Signal voltage, FSB voltage) - VTT is basically the strenght of the signal used on the FSB. It's not changable on most boards, and can easily kill off a CPU if used incorrectly, but it can also greatly improve overclockability if used correctly.
C1E/SpeedStep/Cool'n'Quiet - These are energy saving technologies that will bump down the multiplier and voltage of your CPU when idle. They do not react to VCore increases, so you might end up with a CPU overclocked on under stock volts. Always disable these.
BIOS (BIOS is BIOS.) - Basic Input Output System. It's the primitive, animal side of your computer. It's the under-a-megabyte-large chunk of code that tells your computer how to function, and is without a doubt the most critical piece of code in your computer. The BIOS setup utility is where you'll be doing the overclocking. The BIOS setup utility is generally just referred to as BIOS, for convenience.
BIOS reset jumper (Also called: Jbat1, CLR_CMOS, RESET) - The jumper or switch on your motherboard that controls the power of the BIOS chip. The BIOS chip always needs power, to sustain the settings you have. If power is removed, your settings are restored to stock. Expect to use this a lot. If the screen won't turn on after an increase in FSB or voltage, don't panic. In 99% of cases, functionality will be restored by a flick of this jumper, and your computer will be ready for another try. If you can't find it, remove the battery (round shiny thing, hard to miss) briefly, for the same effect. Always unplug the computer when using any of these, or they won't work.
Orthos - A stess-testing application you need to test your stability.
That should cover most of the terminology.
Preparations
In most cases, stock cooling won't do for heavy overclocking. You should always look into an aftermarket cooler before overclocking. That's about the only preparation you need. For a 65nm CPU, the temp should be kept under 70C. For a 45nm CPU, it should be under 65C. The lower the better.
Overclocking
If you're reading this guide and just skipped the above part called "Terminology", I recommend you reading through it. If you need this guide, you need the terminology. Seriously.
To start, you need to grow accustomed to your BIOS. Spend an hour and a half just browsing through the settings, googling some strange things you've never heard about, and learning what does what. I can't cover everything you can do in the BIOS in this guide, it's a whole other chapter.
Something good to know, is that F10 is save and quit. You're gonna appreachiate that button after 20 FSB steps. Promise.
To get started, you need to find the overclocking menu of your BIOS setup utiltiy. The name of this changes a lot, and can be something completely irrelevant. You should have found it when you browsed through your BIOS.
In there, you should have settings for FSB, voltages and RAM settings. It's hard to write a generalized guide like this, as different motherboards differ a lot when it comes to overclocking options. Most have at least FSB setting, VCore setting and RAM settings, which usually is enough to get a decent overclock.
The first thing you need to do, however, is usually in a completely other part of the setup, and that is: Disable SpeedStep and C1E/Cool'n'Quiet. Those technologies will basically kill any overclocking you do, due to the VCore adjustments they make.
When that is done, go into your overclocking menu, and put everything to manual, that is on auto. Auto is evil. It'll come to your house and rape your dog, while your kids are watching. You should now have the voltage adjustments and frequency settings available to change.
The first thing to do, is to set the RAM multiplier on the lowest setting possible, resulting in as low of a RAM speed as possible.
To overclock, you need to slowly raise the FSB. If you're new, which you are, if you're reading this to get help, I recommend doing one larger step to start off (20-30MHz), and then proceed with smaller steps (5-10MHz). After every change in FSB speed, boot to Windows and run Orthos for 5-10 minutes. If all your cores pass for ten minutes, you're pretty much clear to raise another step. Repeat that procedure until you start getting errors in Orthos.
Then, it's time to raise the VCore. Chances are, that you've already got a pretty decent overclock (400-600MHz, if you're on a C2D). There is no shame in settling for a medium overclock, if you're not willing to kill off some lifetime of your chip. With some lifetime, I mean 20 years to 15 years. Something pretty insignifigant.
You should be real careful with VCore. You don't want too much, as that'll produce unneccesary heat and take lifetime, and too little will sacrifice stability. Raise by the lowest unit possible, reboot, stress test. When you stop getting errors, raise the VCore one or two steps (assuming they're 0.01-0.0125v steps), and continue raising the FSB. Repeat the above steps until you reach an overclock you're happy with, or reach a clock wall.
On a 45nm CPU (E7xxx, E8xxx, Q9xxx), VCore should never exceed 1.4 volts. Anything over 1.4 volts will be hurtful for the CPU, if used for prolonged periods.
On a 65nm CPU (E2xxx, E4xxx, E6xxx, Q6xxx), VCore should never exceed 1.55 volts, for the same reasons.
I currently don't have any voltage guidelines for AMD, sorry.
If you reach a point where no ammount of VCore gives any improvement, you could have hit an either FSB or a CLOCK wall. An FSB wall can be worked around, a clock wall can't*. Assuming that you've hit an FSB wall, you need to increase your Northbridge voltage. It can usually not be raised as discretely as the VCore, but Northbridges are still made with really thick (130nm) fabrication process, so they can take quite a lot of voltage. Raise it by one unit, and stress test. If no ammount of Northbridge voltage will help, either, you've hit a clock wall, and you've basically maxed out your chip. If it helps, repeat steps 1 and 2. I wouldn't recommend feeding more than 0.3 volts more than stock to your Northbridge. If your RAM is above it's stock speed, raise the RAM voltage. Most DDR2 RAM will run fine on 2.1 volts (DDR1 2.8). If it works, repeat steps 1 and 2.
Now only one thing remains - to get it stable.
"Stable" is a term without a definition. Generally, 10 hours of stress testing on all cores is enough to call it stable. You need to back down your FSB in small steps, 1-5MHz, maintaining your VCore, running stress tests in between changes. When you've backed down a bit, you won't get any errors in Orthos. Now, only turn up the RAM speed to match your stock RAM speed as closely as possible, assuming it's below stock.
Congratulations! You've reached a stable overclock!
*A clock wall can, in some cases, be helped by raising the VTT. I strongly advice you not to raise your VTT by more than 0.2 volts. If you have the possiblility to change VTT, and believe that you've hit a clock wall, raise it by as low units as possible.
Freezer7Pro 2008 - All rights reserved. Any suggestions for improvements will be considered. If you notice anything incorrect, please tell me, and I will fix it ASAP.
Version index
v1.0 - 25/07/08
v1.1 - 25/07/08 - Added thermal guidelines
v1.2 - 25/07/08 - Added "RAM Divider" to terminology
v1.3 - 25/07/08 - Added warnings
v1.4 - 26/07/08 - Slight adjustments to the VCore section and additional RAM divider info.
A VERY LARGE MAJORITY OF OEM (Dell, Acer, Fujitsu-Siemens, etc) BIOSES ARE LOCKED, AND HAVE NO OVERCLOCKING OPTIONS. IT IS GENERALLY IMPOSSIBLE TO OVERCLOCK THE CPU IN AN OEM MACHINE.
OVERCLOCKING CAN VOID YOUR WARRANTY. INTEL CAN TRACE IT IF YOU PUMP 1.7V INTO YOUR BRAND NEW 45NM CPU. OVERCLOCK ON YOUR OWN RISK!
(The real risk of damaging anything, if you do it right, is, however, really slim.)
Terminology
You won't need most of this, but it's good to know, and I don't want an excessive number of Xfire adds.
Term (Other popular names) - Description
VCore (Also called: CPU voltage, CPU VID (rare), Core voltage) - it's the main voltage of your processor. The higher, the higher clocks you can reach. Going too high will make your CPU degrade over time.
FSB (Usually just called FSB, short for Front Side Bus) - It's the speed of the bus your processor is on. Raising this will raise the processor's speed, and it's the main thing used when overclocking a processor.
Multiplier (Also called: Multi, x, FSB multiplier) - The number of times your FSB is multiplied to create the final CPU speed. A multiplier of 10x on a 266MHz bus equals a 2.66GHz CPU. Can generally only be changed to a lower value.
RAM multiplier (Also called: RAM Divider) - The number of times the FSB (not quad-pumped) is taken to create the RAM speed. A 200MHz FSB with a RAM multiplier of 2 makes for 400MHz RAM. Most RAM is a variant of DDR, which basically means that the RAM has double the effective speed of the bus it's on. 200MHz DDR equals 400MHz effective. DDR800 (PC6400) is really 400MHz, but due to it being DDR, it's 800MHz. A RAM divider of 1:1 (Often called 2.0 on Intel chipsets) means that the RAM runs at the same speed as the FSB.
Quad-pumping (Not called anything else) - A technology used to improve bandwidth on buses. A single-pumped bus signals once every top of the pulse. A double-pumped signals on every top and bottom, and a quad-pumped signals every top, bottom and middle. A quad-pumped bus of 266Mhz equals 1066MHz effective. The final frequency of the CPU is, however, counted from the single-pumped speed.
Northbridge (Also called: MCH, NB) - The chip that connects all the buses in your computer, PCI-E, FSB, etc. It often requires more voltage to reach high FSB speeds. In some cases, it might even need additional cooling.
PCI-E bus (Also called: PCI-E frequency) - the bus that your graphics card, and possible other PCI-E devices lie on. This should remain at 100MHz all the time, and is generally not a concern when overclocking.
RAM voltage (Also called: DDR voltage, memory voltage, vMEM/Vmem) - The voltage of your RAM. It might be neccesary to raise, if you've reached an FSB speed higher than the speed of your RAM, as many chipsets won't let you choose RAM:FSB ratios lower than 1:1.
VTT (Also called: Signal voltage, FSB voltage) - VTT is basically the strenght of the signal used on the FSB. It's not changable on most boards, and can easily kill off a CPU if used incorrectly, but it can also greatly improve overclockability if used correctly.
C1E/SpeedStep/Cool'n'Quiet - These are energy saving technologies that will bump down the multiplier and voltage of your CPU when idle. They do not react to VCore increases, so you might end up with a CPU overclocked on under stock volts. Always disable these.
BIOS (BIOS is BIOS.) - Basic Input Output System. It's the primitive, animal side of your computer. It's the under-a-megabyte-large chunk of code that tells your computer how to function, and is without a doubt the most critical piece of code in your computer. The BIOS setup utility is where you'll be doing the overclocking. The BIOS setup utility is generally just referred to as BIOS, for convenience.
BIOS reset jumper (Also called: Jbat1, CLR_CMOS, RESET) - The jumper or switch on your motherboard that controls the power of the BIOS chip. The BIOS chip always needs power, to sustain the settings you have. If power is removed, your settings are restored to stock. Expect to use this a lot. If the screen won't turn on after an increase in FSB or voltage, don't panic. In 99% of cases, functionality will be restored by a flick of this jumper, and your computer will be ready for another try. If you can't find it, remove the battery (round shiny thing, hard to miss) briefly, for the same effect. Always unplug the computer when using any of these, or they won't work.
Orthos - A stess-testing application you need to test your stability.
That should cover most of the terminology.
Preparations
In most cases, stock cooling won't do for heavy overclocking. You should always look into an aftermarket cooler before overclocking. That's about the only preparation you need. For a 65nm CPU, the temp should be kept under 70C. For a 45nm CPU, it should be under 65C. The lower the better.
Overclocking
If you're reading this guide and just skipped the above part called "Terminology", I recommend you reading through it. If you need this guide, you need the terminology. Seriously.
To start, you need to grow accustomed to your BIOS. Spend an hour and a half just browsing through the settings, googling some strange things you've never heard about, and learning what does what. I can't cover everything you can do in the BIOS in this guide, it's a whole other chapter.
Something good to know, is that F10 is save and quit. You're gonna appreachiate that button after 20 FSB steps. Promise.
To get started, you need to find the overclocking menu of your BIOS setup utiltiy. The name of this changes a lot, and can be something completely irrelevant. You should have found it when you browsed through your BIOS.
In there, you should have settings for FSB, voltages and RAM settings. It's hard to write a generalized guide like this, as different motherboards differ a lot when it comes to overclocking options. Most have at least FSB setting, VCore setting and RAM settings, which usually is enough to get a decent overclock.
The first thing you need to do, however, is usually in a completely other part of the setup, and that is: Disable SpeedStep and C1E/Cool'n'Quiet. Those technologies will basically kill any overclocking you do, due to the VCore adjustments they make.
When that is done, go into your overclocking menu, and put everything to manual, that is on auto. Auto is evil. It'll come to your house and rape your dog, while your kids are watching. You should now have the voltage adjustments and frequency settings available to change.
The first thing to do, is to set the RAM multiplier on the lowest setting possible, resulting in as low of a RAM speed as possible.
To overclock, you need to slowly raise the FSB. If you're new, which you are, if you're reading this to get help, I recommend doing one larger step to start off (20-30MHz), and then proceed with smaller steps (5-10MHz). After every change in FSB speed, boot to Windows and run Orthos for 5-10 minutes. If all your cores pass for ten minutes, you're pretty much clear to raise another step. Repeat that procedure until you start getting errors in Orthos.
Then, it's time to raise the VCore. Chances are, that you've already got a pretty decent overclock (400-600MHz, if you're on a C2D). There is no shame in settling for a medium overclock, if you're not willing to kill off some lifetime of your chip. With some lifetime, I mean 20 years to 15 years. Something pretty insignifigant.
You should be real careful with VCore. You don't want too much, as that'll produce unneccesary heat and take lifetime, and too little will sacrifice stability. Raise by the lowest unit possible, reboot, stress test. When you stop getting errors, raise the VCore one or two steps (assuming they're 0.01-0.0125v steps), and continue raising the FSB. Repeat the above steps until you reach an overclock you're happy with, or reach a clock wall.
On a 45nm CPU (E7xxx, E8xxx, Q9xxx), VCore should never exceed 1.4 volts. Anything over 1.4 volts will be hurtful for the CPU, if used for prolonged periods.
On a 65nm CPU (E2xxx, E4xxx, E6xxx, Q6xxx), VCore should never exceed 1.55 volts, for the same reasons.
I currently don't have any voltage guidelines for AMD, sorry.
If you reach a point where no ammount of VCore gives any improvement, you could have hit an either FSB or a CLOCK wall. An FSB wall can be worked around, a clock wall can't*. Assuming that you've hit an FSB wall, you need to increase your Northbridge voltage. It can usually not be raised as discretely as the VCore, but Northbridges are still made with really thick (130nm) fabrication process, so they can take quite a lot of voltage. Raise it by one unit, and stress test. If no ammount of Northbridge voltage will help, either, you've hit a clock wall, and you've basically maxed out your chip. If it helps, repeat steps 1 and 2. I wouldn't recommend feeding more than 0.3 volts more than stock to your Northbridge. If your RAM is above it's stock speed, raise the RAM voltage. Most DDR2 RAM will run fine on 2.1 volts (DDR1 2.8). If it works, repeat steps 1 and 2.
Now only one thing remains - to get it stable.
"Stable" is a term without a definition. Generally, 10 hours of stress testing on all cores is enough to call it stable. You need to back down your FSB in small steps, 1-5MHz, maintaining your VCore, running stress tests in between changes. When you've backed down a bit, you won't get any errors in Orthos. Now, only turn up the RAM speed to match your stock RAM speed as closely as possible, assuming it's below stock.
Congratulations! You've reached a stable overclock!
*A clock wall can, in some cases, be helped by raising the VTT. I strongly advice you not to raise your VTT by more than 0.2 volts. If you have the possiblility to change VTT, and believe that you've hit a clock wall, raise it by as low units as possible.
Freezer7Pro 2008 - All rights reserved. Any suggestions for improvements will be considered. If you notice anything incorrect, please tell me, and I will fix it ASAP.
Version index
v1.0 - 25/07/08
v1.1 - 25/07/08 - Added thermal guidelines
v1.2 - 25/07/08 - Added "RAM Divider" to terminology
v1.3 - 25/07/08 - Added warnings
v1.4 - 26/07/08 - Slight adjustments to the VCore section and additional RAM divider info.
Last edited by Freezer7Pro (2008-07-26 03:21:15)
The idea of any hi-fi system is to reproduce the source material as faithfully as possible, and to deliberately add distortion to everything you hear (due to amplifier deficiencies) because it sounds 'nice' is simply not high fidelity. If that is what you want to hear then there is no problem with that, but by adding so much additional material (by way of harmonics and intermodulation) you have a tailored sound system, not a hi-fi. - Rod Elliot, ESP
