[HOW TO] Intel CPU Overclock Basics

Discussion in 'Tutorials, Guides & FAQs' started by DirtiDodger, Jan 5, 2017.

Is your CPU Overclocked?

  1. Yes

    2 vote(s)
  2. No

    3 vote(s)
  1. DirtiDodger

    DirtiDodger New Member

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    I appreciate the number of gamers and enthusiasts that browse forums who will probably find this information to have no use, but for some of those who are reserved on popping cherries with pushing electronics beyond there manufacturing boundaries, I thought I would post up a not so intricate guide to unleashing the potential of your Intel CPU!
    The information provided in this guide is a concoction of research I have completed, but more importantly my own experience and knowledge with the process from trial and error. There is a lot of information on plenty of sites to be found, albeit taking all aspects into account, can be very tricky to make heads or tails of.

    My aim is simple. To provide a basic understanding of how overclocking is acheived and give you a basic knowledge base to take away and start overclocking yourself.

    Feel free to compare this to other 'guides' and if you have any edits, options or inputs you find conflicting from your own expereince let we know, im always happy to learn and expanded my knowlege on these things. This is the first time ive ever done something like this so go easy, i hope its ok.

    Break Down
    1) Overclocking.... What Is It?
    2) Pros and Cons
    3) Temperatures and Voltages
    4) Temperature Reduction
    5) Monitoring And Testing Software
    6) Starting Your Overclock
    7) Stability Testing
    8) Review/ Summary

    1) Overclocking.... What is it?
    'overclock' (OC)
    verb (used with object)
    Computers; to modify (a hardware component, as a processor, graphics card, or memory) so as to increase the speed of that component beyond the specifications of the manufacturer:
    You can overclock your CPU to improve its performance.

    For this guide and for us to complete a simple overclock, we will be changing two main values in the BIOS menu which is loaded during boot up. These values are Core Multiplier and VCore.

    Core Multiplier - This is part of what determines the internal frequency of a processor. CPU speed uses the speed of the Front Side Bus [FSB] multiplied by the Core Multiplier to produce the internal clock frequency. Ie- FSB speed of 100Mhz, with a Core Multiplier of x34 will give us;
    100Mhz x 34 = 3400Mhz or 3.4Ghz.

    VCore - CPU Core Voltage or VCore, is the amount of voltage being supplied to the CPU by your power supply. If the Core Multiplier is increased, the VCore will need to be raised to meet its new requirements to work (be stable). More voltage = increased temperatures. We shall look at this shortly.

    2) PROS and CONS
    For the pros and cons we shall focus on the ones that i feel are the most relevant to the basic/starter overclocker. This may vary based on your own opinion though.

    -The main PRO from this then, which is fundamentally why we do it; to gain better performance from our CPU. Sometimes these gains can be marginal, but other times can be significantly larger. We shall look at how and what effects this outcome later.

    -This can be a fun and interesting hobby. Unbeknown to you, it may open the door to another part of the PC building/modding world you never knew existed and provide you with hours and hours of fun tinkering and testing. People actually compete to push systems to their absolute limit. Some CPU's pushing excess of 8Ghz with liquid nitrogen cooling.

    -Consistently high temperatures due to high input voltages can potentially cause permanent damage to not only your CPU but other hardware as well. It is important that you don't go at this like a bull in a china shop. It must be taken slow and steady, step by step and the likelihood of any damage will be greatly reduced.

    -Higher then usual temperatures can sometimes decrease the lifespan of your electronic components. Heat is the main killer of electronics here. Adequate cooling is integral if you wish to gain the most from your OC. So don't skimp on your cooling, not only will it help increase your OC'ing head room, it will also increase CPU longevity at its increased power draw.

    3) Temperatures and Voltages
    For temperatures we will have a look at a few of the different types involved with overclocking and how some effect the over all result. We will also look over the relationship between voltage and temperature.

    CPU Temp - This can be viewed as the overall CPU temperature (all cores). The original test is ran by Intel for their thermal specification database and is actually measured from the surface of the integrated heat spreader (IHS). For most of the modern I-processors with 1150, 1151 and the 2011 sockets, they use the hottest core for this reading. Depending on certain software, it may also be given as a average of all core temperatures.

    Core Temp - You guessed it. This is the temperature of any given core measured by thermal sensors located on the 'transistor junctions' and so it can also get called Tjunction. Intel recommends using a variation of +/-5 oC with measurements taken from these sensors. For the software used in monitoring whilst overclocking, these temperatures are going to be the ones you will monitor. This is due to their reactivity to changes in CPU load and will almost instantly increase as the loading does.

    I found a handy table created to indicate decent operating ranges of Core temperatures.
    80C Hot (100% Load)
    75C Warm
    70C Warm (Heavy Load)
    60C Norm
    50C Norm (Medium Load)
    40C Norm
    30C Cool (Idle)
    25C Cool

    Please remember these are only a guideline. I have read articles by people who never wish to reach the 80 mark, but also others who are happy to reach high 80's. As a safe medium and taking into account the +/-5 variation I would settle with around 80 oC at maximum load for a prolonged period of time and/or stress testing. But ultimately, the lower this figure, the better longevity of your CPU.

    Throttling Temperature
    - Also known as TjMax. This is the temperature at which the CPU will reduce its internal clock speed to help protect itself from any damage caused by further heat build up. I have had this happen one of the first times I started to overclock. Turned out to be inadequate cooling but we will look at ways to prevent reaching this in the next section.

    Ambient Temperature - Otherwise known as Room temperature. This is the temperature that is measured externally just before the air intake fans on a tower. This air is ultimately travelling into and around your internal components and so the without saying, the cooler this air is, the better. Not only will it help reduce internal temperatures but it will also allow for a larger overclocking headroom if ambient temperature in generally quite low. This can and will effect ALL of your computer temperatures.

    Voltage and Temperature - As I mentioned earlier if you raise the Core Multiplier to increase the clock speed, to maintain stability you will need to raise the voltage well. As a result, more power is used and thus more heat is dissipated.
    No two CPU's are the same due to the manufacturing process and each have their own individual properties when dealing with an increase of voltage. This inevitably changes the overclocking potential of each chip. This is referred to as 'silicon lottery' in the hope you have purchased a chip that deals well with the above and allows a better OC.

    Remember - 'excessive VCore and temperatures can result in accelerated Electromigration'
    Basically, you can fry your chip!

    4) Temperature Reduction

    Here we will have a look at some of the variables we can alter to help reduce temperatures before, as well as during the overclocking process. All of these will aid in increasing your potential to overclock further. The lower you keep your temperatures, the further you can push or the longer you can maintain stability in your system.

    CPU Cooler
    - Whether its air cooled or liquid cooling you use, without it this would be far more difficult. This is the primary cooling means for the heat produced not only during overclocking but for the CPUs day to day work. Second to liquid cooling, the position and type of air you use for cooling can also aid in reducing or increasing other temperatures within your case. Ie - Top mounted exhaust will vent warm from inside the case, but as it is using the warm air from inside to pass through the radiator it results in slightly lower cooling peformance. On the other hand if it was a top mounted intake, cooler air from outside the case would be bought in through the radiator to cool the CPU producing better performance. Caveat to this, you can expect to see slightly higher temperatures on your GPU/RAM as a result of the warm air being pushed into your case from the radiator.

    Case Design - Big open spaces allow for plenty of air flow. Having a larger case will allow for this providing you have supporting fans to provoke the right air flow throughout. Midi towers are often smaller and compact so correct cable management is vital to prevent disturbance to cooling air flow. Full towers are much larger and are used for much bigger PC builds or those who wish to promote a much larger amount of air flow. These cases can be quite big in size, and price.

    Cable Management - The art of cable management. Whether its hiding cables to have a tidy presentable computer, or moving them to keep them out of the way of the intake air flow, keeping this neat and organised will only aid in preventing dust build up but also freeing up room for air to pass over your components and cool them further.

    PC Location - The location of your actual tower can also have a small effect on temperatures. Not ideal - placing it next to a radiator for example. More ideal - having it raised up slightly off the floor and in a location that has relatively good ventilation. Try not to block intake and exhaust areas and allow unrestricted access for air to escape.
    If your overclocking to see how far you can push it, by all means do what you can to lower the temperatures as much as possible. Remove panels or place it by and open window to fresh cool air. If however you are setting an overclock to use for a day to day use, I would personally keep the tower where you wish to use it. Try not to cheat cooler air into the system when you overclock as the temperatures you see, will no doubt increase if you put the tower back down on the floor under your table/desk.

    Thermal Paste - Choosing an adequate thermal paste is important as it not only acts as a protective layer, but it is many more times conductive and allows for a better transfer of heat between the CPU and its heat sink. Too little paste and it will not aid conduction, too much paste will also prevent it. Make sure you apply the right amount in the right place and every so often, remove, clean and re-apply the paste for maximum efficiency.
    This was the issue I had with my first experience. I had an all in one (AIO) water cooling system. Why the system was adequate at keeping temperatures kind of cool, the paste that came with the set was not. It wasn't allowing the right amount of heat transfer which increased my temperature to point of throttling. Only advice I could give from that is don't just buy the cheapest paste.

    Core Voltage/Speed - Both of these will have an effect on the temperature of each Core and so the CPU temperature as a whole. The faster the processor works the more heat it'll produce. For the processor to work faster it'll require more power (Voltage) and more Voltage produces more heat. The trick here is to keep the Vcore as low as possible to prevent excess heat build up whilst maintaining a stable overclock.

    Other Hardware - Other hardware installed in your computer under load will also produce heat, and these may also be OC'd producing further more heat. The GPU cooler on most cards are fans facing downwards. Unless there is an exhaust fan placed towards the bottom of the case, this hot air will be re-circulated and remain inside the case. If you have sufficient intake fans this should allow exterior, cooler air to be sucked in and have a cooling effect before being vented by the exhaust fan(s) elsewhere.

    5) Monitoring And Testing Software

    So we've had at the variables we can change and how an increase in either of these can contribute to higher performance but also higher temperatures.
    We have also touched on factors that can change the temperature of your system and ways to help reduce internal temperatures to aid keeping your CPU cool and increase your headroom for OC'ing.

    Before we look at the run through on doing the OC we will just take a look at the software we can use for testing and monitoring during the process. It's better to have this software installed and understood before starting which will help you analyse the data it's displaying you during the tests. This should give you a better understanding on how your computer is reacting to the OC.

    CPUID- designed to gather information on some of your hardware such as your processor name and number, it's codenames, the cache sizes, speed and some others. Displays memory type, size and timings.
    It also displays in real time the internal core frequency along with memory frequency too. Find out more and download from here www.Cpuid.com

    HWinfo - designed to gather system information. It also provides real time monitoring with the vast array of system info it provides.
    It accommodates for a user generated interface which helps to minimise clutter and to let you focus on what you specifically wish to monitor.
    Find out more and download here www.hwinfo.com

    RealTemp - designed for temperature monitoring with intel CPUs. You can adjust settings for each of the cores and it also allows you to set and adjust alarms for throttle limits to help prevent damage. It provides you with current core temperature, distance to Tjmax (throttle temp), minimum and maximum recorded temperatures too. Also has a built in sensor test to check your Digital Thermal Sensor (DTS) on each core.
    Found here at www.techpowerup.com/downloads/SysInfo/Real_Temp/

    Aida 64 - this is another piece of software developed to gather system information and provide a useful tool for diagnosis and benchmarking. There is a purchasable version, but also the free trail version with limited features. This allows for the monitoring of your hardware with Aidas' built in stability test. It's lets you configure the test to run on a variety of your hardware and CPU components.
    Info and download at www.aida64.com

    Prime95 - I believe this is the one most commonly used by folk for OC stability testing. This program runs the CPU at max workload and continues to do so until an error occurs. Most other system testing software does not run testing at the same level of intensity as Prime95. Chances are if you can run this for a prolonged period of time you have a stable OC. Monitor your temperatures closely here as they can get high and quick.
    Grab a copy of the software here www.mersenne.org/download/

    Intel burn test - IBT, just like P95, is a stability testing program designed to push your CPU to the limit. This will also give you a good indication of any system stability issues. Most people find that p95 and IBT are a bit too much, but if you can maintain stability for a decent amount of time with manageable temperatures your on to a winner.
    IBT can be found here www.techspot.com/downloads/4965-intelburntest.html

    6) Starting your Overclock

    Quick recap on some stuff from above before we start.
    PC location; place it where you plan to use it, but take into account good ventilation.
    Monitoring software; download it, get to know it and use its potential to your advantage. It may also be worth running a stability test with a few of your chosen software prior to OC'ing. Make a note of your VCore, Clock speed and more importantly your temperatures. That brings me to.....
    Piece of paper and a pen; I think its handy to make note of the changes you've made and the effect it has on a few of the mentioned variables. Make a handy little spreadsheet to keep track of your work.

    More experienced overclockers may jump in and up thier Core Multiplier lets say from x34 straight to x40. They will then make an (experienced) guesstimate for the VCore based on the CPU specs and previous experience. For us though this isnt really reccomended. With a lesser understanding of how our CPU will react to voltage input changes, it isnt really advised to put in a high voltage immediatly. Get a feel for it as you work your way up step by step, each time reaching a higher OC, saving your stable config on your BIOS menu. This can be used to revert to in case the next OC produces instability.

    Please be aware the actual names may vary from motherboard (mobo) to mobo, so be 100% sure you have selected the correct figure before changing it. If you are unsure how to navigate your UEFI/BIOS menu do a quick google search of your mobo and familiarise yourself with it.

    1) Enter BIOS

    • Start/Restart your PC. Before Windows boot is complete hit the 'del' key.
    • Click 'Profiles' and save your current config. 'Default' may already be saved in which case you can create a seperate backup or use the 'default' to fall back onto initially.
    • Disable 'Intel Turbo Boost'. This may be found under 'Performance', 'CPU Settings' or 'Adv Freq Settings'. Loacte ITB, click the drop down box and select 'disable'
    • Under 'Performance' locate the CPU VCore drop down box and set 'manual' or enter the VCore your standard clocked CPU used on the tests you ran prior to starting.
    The two in red should need only be done once. But it may still be worth checking that these values have been saved once your reload into BIOS. Subsequent checks therefore arent necessary.

    2) Up the Core Multiplier

    • On 'Perfomance' or 'CPU settings' you will find one named Core Multiplier/Clock Ratio. This number will vary depending on your CPUs final clock speed. Up this number by an increment of 1. (Ie- x34 now becomes x35)
    • Save and Exit to restart your PC. (for this i would save as '3.5 GHz Test')
    3) Stability Test
    • The first test here will be to see if Windows boots. If you sucessfully load into Windows you can now open up your monitoring and testing software. Once you are all set up and ready to go, hit run on your chosen test! The next section will help you come to a conclusion abouts what a 'stable' system can mean to you. If you are happy it is stable and temperatures are with limits then go to step 1
    • If however at any point, whether it be during windows boot up you receive a blue screen of death (BSOD) or perhaps during stress testing you crash, this indicades an unstable OC from low voltage. If you are satisfied its unstable go to step 4
    4) Up the VCore
    • As the system restarts from the crash, before Windows boots again get back into the BIOS menu like before.
    • Locate the VCore, now increase this value. I recomend an increase value of 0.05v to start with. You can fine tune later once you reach nearer the limit of your OC. Save and Exit BIOS to restart your PC. go to step 3
    It really is just a case of repeating this cycle by initally upping the Core Multiplier, then finding the right VCore to obtain a stable system. Push this process as far as you wish to reaching your max operating temperature limits. If you increase the OC to the point where you are unhappy with the temperatures its producing, simply revert back to your previous stable clock and fine tune from there. few

    7) Stability Testing

    I've mentioned stability/stress testing a few few times now. In this section ill just briefly explain a few things about this process and what stability is. But as a whole we are looking at the CPU being able to fully function no matter the loading placed upon it. There are various ways in which we can test this to.

    What is it then?
    The main idea is to push your CPU in certains areas (or all of them) to the absolute limit. The intensity of the test is applied continuously until either, failure, or the test is manually ended. Doesnt crash = stable, crash = unstable to simply put it.
    Dont confuse this process with benchmarking though as this is primarily used to test a hardwares performance, not its stability.

    How do we acheive stability?
    We had a look at how this 'stability' is gained. If the Core Multiplier is raised, the VCore must be suffecient enough to the point where it can support the CPUs needs. If it doesnt, then it will produce an unstable system and will result in a system crash. Stability is classed as a system that, when under max load, can indefinatly perform without crashing to a BSOD or shutting itself down to prevent damage.

    How we test it?
    There are a variety of different testing softwares we can use to push our CPU to the limit. Some were covered in Section 5. Each of these have their own 'intentisy levels' as it were. Some of these can also specifically test certains areas of your CPU such as the Cache or FPU. Intensity in tests can vary your temperature results. Have a little play around and run different tests to see how each piece of software pushes your OC, remember to watch those temperatures.

    Another good idea which may not be so CPU intensive as a stress test, is to run a more CPU reliant based game. If you are overclocking for gaming reasons, what better way to test your system then putting it through its paces with the main thing you built it for. Even with my current overclock, P95 runs my temperatures upto 80-85oC. Since using it for gaming the highest temperature ive seen has been about 75oC. A considerable drop. This shows a noticbale dfference in loading during stress testing and gaming. I could probably push my clock a little further to run it hotter during gaming, but i wouldnt be able to run P95 as i would most likely reach TJMax.

    8) Summary
    To summarise a few ciritcal points for each of the sections:

    • Overclocking is essentially pushing your CPU beyond its designed specification.
    • Core Multiplier and VCore are the variables changed to achieve an OC.
    • Cooling is extremely important if you wish to OC. The more you can cool, the further you can push it.
    • Increasing Voltage will increase heat. Make sure you have some accurate monitoring software and watch those temperatures.
    • Take it step by step to start with. Be sure you mark down your results and what changes you have made to keep note.
    • Save each stable config in your BIOS as a fall back option
    • Most importantly, have fun!
    I hope you managed to take something away from this guide/how to. As i said before, if you have any comments, remarks, edits or conflicting experience please comment below and share. Im always happy to continue learning about these things.


    Last edited: Jan 5, 2017
    Luxxx Maximus and zeus_anoxia like this.
  2. LulaNord

    LulaNord New Member

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    Hi...i am a new user here. I have few queries:
    Is it possible to overclock an Intel I5-6400 CPU on an ASUS Z170-E motherboard with latest UEFI BIOS 3007 (11/29/16)?I've done a ton of web reading and watching videos, and it seems Intel has blocked overclocking non-K CPU's, even with a modified BIOS.Am able to overclock the memory (and GTX 1050 TI GPU), but nothing I've tried gets the CPU to actually run above 3.3mhz.
    BoredGamerUK likes this.
  3. Raumarik

    Raumarik New Member

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    Some motherboard chipset also block CPU overclocking as they aren't considered enthusiast level even with a K series. Always best to check first.

    I've always seen more benefit from OC'ing graphics cards personally so it's not something I'm too bothered about. The CPU OCs tend to be very marginal and not really visible in-game.
  4. Luxxx Maximus

    Luxxx Maximus New Member

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    Just a tip for newbies that do their 1st overclock. Check the Intel forums for manufacturer suggestions for you CPU overclock. Do not try to push over the limit, after all, they tested it....
  5. DirtiDodger

    DirtiDodger New Member

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    Hi LulaNord!
    I must agree with Raumarik. Certain mobos actually don't allow OC, or in fact any self voltage regulating at all, which would also mean no no for memory too. Looking at your CPU , it's a non 'K' 6400 which does mean intel have prevented this chip from being overclocked. In some cases with certain boards and UEFI, your right, over clocking a non K can be achieved. By the sounds of it in your case this may not be achievable. Not to worry!

    A great gain in FPS can be obtained by overclocking your GPU Common software such as MSI afterburner or EVGA precision X will help you safely overclock it!

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