As with any advice given at THGF regarding overclocking, neither I, 4Ryan6, Toms Hardware Guide, or the owners, Best of Media, take any responsibility for you overclocking your own hardware, you take sole responsibility for your own actions in using the information in this guide!
Unfortunately for us all, every motherboard BIOS is different and these settings, features, and naming terminology are taken from an ASRock P67 Extreme 4 motherboard BIOS. This guide is written assuming you are familiar with your motherboard BIOS, and how to maneuver, change settings, and Clear CMOS, (CLRCMOS1), when needing to do so.
Danger: Going past 1.500v is not recommended unless you have an extremely good cooling solution, meaning high end water cooling, air cooling is not a sufficient cooling solution for the heat this overclock generates, or you will be thermal throttling and not realize it. If you choose to disable thermal throttling you could very well loose your CPU from the voltage/heat required to reach the higher multipliers, remember 1.520v is Intel's tested maximum limit at the time this was written! See: Page 75 Table 7:1
The method I'm going to share here disables all Intels energy saving features, it also disables Turbo Boost, so if you want to run those features, stop reading right now, this is not the guide you need.
This guide will allow you to overclock all 4 cores, with no voltage or multiplier throttling, as long as you can keep it cool enough, make sure you have more than just adequate cooling, when overclocking all the cores, (Especially if you're overclocking a SB/K CPU with Hyper Threading capabilities, Enabled!).
Manually set your Memory Timings and Memory Voltage requirements to their exact specifications. (Very Important) This will be your best initial route to take, you want your memory literally bulletproof and stable when raising the multipliers to higher levels. Your M/B may have an XMP preset profile that automatically sets your memory to run at it's rated speed, I strongly suggest not using that feature.
Memory Note:1T and 2T settings need to be tested for stability, I recommend you start with the 2T setting and when you reach your goal, then see if it will remain stable if you use the 1T setting.
Disable these Intel CPU features, Enhanced Halt State (C1E), CPU C3 State Support, Package C State Support, C6 State usually on a Z68 M/B, Hardware Prefetcher, Adjacent Cache Line Prefetch, No-Execute Memory Protection, Spread Spectrum, Intel Virtualization (Unless you're running WinXP virtual within Win7, in that case leave it enabled)
Intel Speed Step Special Instructions: Before you disable Speed Step, which disables Turbo Boost, set Turbo Boost Power Limit to [Manual]
Set Short Duration Power Limit to 140
Set Long Duration Power Limit to 180
Set Long Duration Maintain to the max allowed sec. (Mine is 56)
Additional Turbo Voltage (Mine is set to +0.527 and is working fine, Too little is not good and too much is not good, you'll have to figure this one out for yourself, if the voltage I'm using will not work for you)
BIOS save these special instructions exit and re-enter the BIOS and then disable Intel Speed Step
Leave CPU Thermal Throttling and Internal PLL over voltage, [Enabled]
Active Processor Cores = All
Core Current Limit = 200
CPU Ratio = Manual (This is the control to manually set your multiplier, you will be adjusting this, increasing for higher clocks)
Host Clock Overide or Base Clock = 100mhz
Power Saving Mode = Disabled
CPU Core Voltage = Fixed
Fixed voltage = (the voltage it takes discovering through trial and error, setting, booting, and re-booting, to run a certain multiplier.)
CPU Load Line Calibration = Level 1
DRAM voltage = (Set to Memory Module Specs)
Leave all the rest of the voltage setting on AUTO, PLL, VTT, etc.
Now that the settings have been set that will not be changing, you're to a point where you simply trial and error boot to discover what manually set CPU fixed voltage (Adjustable), will stably run the multiplier, (Adjustable) you choose.
Testing to Stability:
When getting in the stability ballpark Prime95 Small FFTs will allow you to discover your first level of stability, then run the Blend Test which normally takes an increased bump or two higher Vcore to acquire stability, or if no Vcore increases past Small FFT stability gains Blend Test Stability, you’ll need to drop your memory speed down and continue testing until you gain stability.
Or if you want to shorten your testing to stability you can use IBT, (Intel Burn Test), but P95 Blend does help pinpoint memory timing problems, so it really is a personal preference as to which of those programs you use.
Memory Note:Some memory modules will not run their rated factory spec'd speeds at the higher achievable Sandy Bridge K Series multiplier levels. Just because your memory is rated at say 1600mhz, 1866mhz, or 2133mhz, does not mean it can run 1600mhz, 1866mhz, or 2133mhz at a 45x, 46x, 47x, 48x, 49x, or 50x + multipliers.
None of those modules were factory tested at those multiplier levels, you have to discover what your memory modules are capable of, before you depend on them further down the road of increasing your multiplier and testing for stability, or you’ll be proceeding on a false assumption, thinking you are stable when you are not.
OK, I’m CPU stress testing stable now according to P95 or IBT, so am I system stable now?
No you’re not!,
You’ll need to weed out the problems that come to the table when the Graphics and Sound enter the picture such as with gaming, or you’ll be Prime95 and IBT assumingly stable and crashing in games
Fine tuning your Vcore setting, I suggest using a combination of benchmark programs such as Futuremark’s, 3DM06, 3DMVantage, or 3DM11, if you have the advanced versions of any of them you can max the testing settings, (Increase screen resolution, and add all the eye candy testing features, like Anti Aliasing, Antistrophic Filtering, etc. Max all you can) and run 2 or 3 loops.
If you encounter crashes increase your Vcore another notch and continue testing until you can run multiple loops without crashing, and you are pretty much very close as far as stability is concerned, add some gaming testing and if you have no crashes at all when sound is brought into the picture you’re good to go, if you do experience an in game crash bump up your Vcore another notch.
Always keep in mind, it’s desirable to run as low a Vcore voltage as you can, however it will take a certain voltage level to be 100% stable at the increased multiplier levels and there’s really no getting around that.
Additionally SLI requires usually a 2 bump Vcore increase from the stability level of testing out a single GPU to stability.
It is just not necessary to run 24 hours of Prime95 as some suggest, you can do that and still crash a few minutes into a game, you’re only increasing the multiplier and Vcore voltage, all your other base settings are default, so weeding out FSB instability is not necessary with this type of overclock.
Anyone reading this should know how important your cooling is, a good aftermarket cooling solution is an absolute must for reaching the higher multipliers stably, and you should monitor your temps with a program likeReal Temp vs 3.70.
Good Overclocking results to you all, and most importantly and have fun doing it! Ryan