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A Guide For Overclocking Your I7

Note boring disclaimer - though overclocking these days is fairly safe if you follow some basic precautions. Any overclock could reduce the life expectancy of your chip and excessive overclocking can kill your chip and or motherboard. I take no responsibility for any fry up you cause !!

With that said relax, OCing an I7 is fairly safe if you are sensible and do not go crazy. Intel 920 and 930 chips have a maximum preset temp of 100 C and Intel have adopted a fail safe system that will throttle the CPU back if these temps are reached ) perhaps before they are reached) you will have to check the max temps for other chips usually called the TJMax

Overclocking and voltage changes go hand in hand and with voltage changes come temperature changes. It is difficult to give exact safe settings for these as your cooling system will vary as will your boldness in pushing your chip. But I would say for this exercise max temps should be not exceed 85 C and Max voltage under load should be no more that 1.40

Now I hope no one will need anything like this, especially the volts which are way over Intel specs, however with the right cooling voltages can be raised substantially it is the heat which will do the major damage. With high end cooling people have used outrageous voltages to get their chips to 5ghz or even 6 GHz. The chips survive the volts because the temps are so low. To put it into perspective I am running at 4.0 GHz with 12 GB RAM on an I7 930 I am also running a stress test (prime 95) as I type and temps are maxed out at 74 C and my volts are 1.296 - well below intels recommendation of 1.36 v

Now I will not bore you with all the geek stuff but I must mention a couple of things. The I7's are very different beasts from previous Intel cpu's, the memory controller is actually on the chip so you really must watch your memory settings when overclocking. The turboboost function may be fun at low CPU settings but I would avoid it for high overclocks, we can get all we need without turboboost. A cpu's frequency is calculated from the base clock (BCLK) multiplied by the CPU multiplier. The lower end ( I7 920 and 930) chips have these locked, the 920 is locked to 20 and the 930 is locked to 21 now turboboost will push these up by one so 21 and 22 respectively Memory speed is calculated by multiplying the BCLK by the memory multiplier ( called SPD in gigabyte boards) so for example I have a CPU multiplier of 21 a background clock of 191 which gives me a CPU speed of 4011 MHz (GHz) a good overclock especially on 12 GB RAM. Now my SPD is at 8 so 8 x 191 = 1528 MHz for my memory which is a tad under the rated 1600, hardly noticeable. RAM sticks should have certain settings given with them and some have what is called an XMP profile built in which helps to auto set them. If you don't have xmp memory you will need to know the basic timing and voltage, typically given as a set of numbers such as these 9-9-9-24-2T voltage 1.65v OK lets get going first of go buy a decent cooler for your CPU, though the Intel stock fan my get you some OC it will not do for 4.0 GHz, it just cannot handle it. I REPEAT - FOR THIS EXERCISE THE INTEL STOCK COOLER WILL NOT COPE, You could try the corsair H50 water cooler but it really is a gimmick and not anywhere close to a proper water setup. The H50 will not cool as well as a high end air cooler I would suggest these coolers, the Titan Fenrir, the Prolimatech Megahalems Rev B or the Noctua NH-D14, in order of price and performance. The Titan may just be usable for 4.0 GHz, the latter 2 certainly are. The Noctua is rated the best but is large and may not fit some cases, always check measurements before you buy. Also most large coolers, especially the Noctua can block RAM slots which is important if you are using RAM with large heat spreads, I use standard Corsair XMS3 6GB (3x2GB) DDR3 12800C9 (1600MHz) Tri-Channel (CMX6GX3M3A1600C9) which fits fine on my gigabyte x58a-ud3r motherboard though I have to remove the cooler to access all the RAM. Note the X58A-UD3R has 6 RAM slots as opposed to the standard X58-UD3R that only has 4. Check your MB has enough ram slots for future upgrading. A cooler needs good thermal paste between it and the CPU. Do not try and use a cooler without some form of thermal solution between it and the processor. I would suggest Arctic Silver 5 ( needs curing time and is conductive - a potential hazard) or MX-2, MX-3 and MX-4. These are non-conducting, and need no curing time.

FIRST TIME OVERCLOCKERS DO NOT PANIC

Hopefully the setiings i give below will work off the bat but as you lower voltages YOU WILL GET BSODs, crashes and windows reboots. So i would advise you back up everything before you start. The crashes and blue screens are all part of the overclocking process, our aim is to get the system stable with a fewer volts ( lower temps) as possible and at some point the settings will be too low for your overclock and instability will occur

You may find it usefull to connect a PS2 keyboard when overclocking as when windows recovers from a crash a USB keyboard will often not work untill you get into windows and you may not be able to use the keyboard for boot menu selections. This is most annoying if windows crashes rather than BSOD as windows offers to do a system file check which you cannot stop with a USB keyboard, if this happens you have to be quick with your mouse to cancel the windows repair program, or make a cup of tea while it does it's funky thing and tells you that it cannot find any errors

So you have you ram in and your cooler on. Now we need some software for testing , search for an download:

RealTemp
CPU-Z
Cinebench
Prime95

You should also get a BIOS reader usually one will come with your MB for overclocking, Gigabyte has easytune though I would not use it for overclocking, use it to check voltages. In your bios set you memory up as specified don't forget the volts (DRAM) Install the above software and fire up cpu-z, realtemp and cinebench.

Cinebench is a great tool, for 3d benchmarking but also serves as a quick safe overclock tester. Prime95 is a more complete torture test and will really push you temps. Cinebench is the first tool to test stability as it is fast and does not push temps that much

With the above open take a note of your volts from CPU-Z and your temps from Realtemp they should be low temps ( below 50) and volts will vary but should be well below 1.3 V Run cinebench, realtemp should stay on top but you will need to restore cpu-z, watch your temps, these should be very low, probably below 60 C note the CPU volts, they should have dropped, this is called vdroop and Intel implement this by default. Many motherboards have a setting to enable load line calibration LLC which will turn vdroop off or lessen it but we will not use that. The point is that under load your voltages will drop and since a certain overclock needs a certain minimum voltage we have to raise the CPU volts in bios above what we expect to see in cpu-z under load as vdroop will lower the voltages. Don't worry too much about the higher volts at idle, it the volts under load that concern us. If you look carefully at the top of the realtemp you should see you BCLK and multiplier fluctuating, this is normal as Intel has power saving features in the bios that lower setting when load is low, many people disable these in BIOS when overclocking and testing then enable them, I do not see the point as we want to get the system stable under normal working conditions. That is why I do things when I am stress testing as I am now, if my OC is stable when running prime95 but crashes when I am in notepad then..well it is not a stable overclock !!

Now fire up you BIOS reader ( Motherboard tuner) and take a look at the voltages, they will all probably read the same as their normal base settings. Good we will not have to deal with these buggers,if that sort of thing turns you on they go crazy messing with them but we really need to touch only a few. If any are way over the normal settings then go back into BIOS and clamp them there. In general the 2 most critical voltages are the CPU volts and the QPI-VTT volts, when left on auto in BIOS they can over volt when over clocking The settings we will adjust are CPU volts QPI-VTT volts the on chip memory controller and maybe CPU-PLL something to do with phase loops !!

First go into your windows advanced performance settings ( right click my computer) and disable auto restart and set no memory dump. If we blue screen we want to see the details If you have an option in you bios to load optimal settings do that now

1. Find and turn off turbo mode

2.For an I7 930 set the CPU multiplier to 21 for an 920 set it to 20

3. Set the BCLK to 191 for an 930 and 200 for a 920

4. Set you RAM to the rated speed and volts

5. Set you SPD to x8 ( or whatever multiplier results in your rated RAM speed or lower)

6. We need to raise the QPI Link Speed which is the quick path interconnect ( links everything up) yours would have been at 4.2 GHz but we need much more so set you QPI multiplier to X36 this will give just over 7.2 GHz Your ram should be just under its rated speed if not lower the spd to get it at or below the rated speed

7. There is a setting called the uncore frequency driven by the uncore multiplier X the SPD, we need the frequency to be at least twice the memory speed in my case the mem is at 1528 so I need a frequency of 3056 I set my uncore multiplier to twice my SPD + 1 ( seems to help stability) that is 8x2 +1 = 17 Now we need to up the CPU voltage to accommodate for the OC, all processors are different and settings may be lower or higher than mine, also 6 GB ram to 12 GB ram makes a difference and those with 6 GB ram may well use lower settings

8. Set your CPU voltage to 1.375 make sure load line calibration is off 9 We need to make sure the on board memory controller has enough volts, especially for 12 GB so set you QPI-VTT to 1.355 That is it, you may also want to dig around your bios for HPET or ACHI and check that it is set for 64 bit if you have a 64 bit o/s, in fact look for all settings that pertain to 64 bit and adjust accordingly Leave all other settings on auto Now reboot and fire up cpu-z and realtemp, check all is well temps are well below 80 C at idle volts are below 1.4 V.

Fire up your motherboard tuner, all volts apart from those we changed should be at normal or slightly higher. maybe 1.16 instead of 1.10, if any are very much higher go back into bios and change these from auto to normal or key in the normal settings.

Now run cinebench it should run without crashing and check your temps are below 85 C and note your volts on the CPU. I find with my 930 and 12 GB RAM that I can drop to about 1.29 V under load and remain stable. Run Cinebench 3 or 4 times, still stable ? If cinebench hangs then it is likely due to low CPU volts, blue screens will give esoteric messages but in general if you see :

101 you need more CPU volts
124 You need more QPI-VTT
0x0-50 check memory times and or uncore multiplier

Most other BSOD's will mean you need more CPU volts On air cooling I would suggest to keep the CPU volts under 1.45 in BIOS, aim to keep them under 1.4 v under load ( preferably below 1.36).

Stress testing is abnormal I would try not to exceed 85 C, this will be a lot less when rendering general projects, in which case I would want to see around 80 Max A few other tweaks that may help, people often push their PCI frequency above 100 to 101 or even as high as 105, CPU-PLL can be raised or lowered, Asus boards can sometime benefit from a raise gigabyte from a drop but you have to experiment When using optimal settings for a gigabyte board the CPU clock drive is set to 800 and the PCIE clock drive is set to 900 for other boards you may have to dig around to find these settings

Now I would suggest you save these settings as a bios profile than go in and lower either the CPU volts or the QPI-VTT and run cinebench again > Keep doing this till cinebench fails or you BSOD in which case raise the volts. Do this till you get you lowest stable cinebench volts

Now fire up Prime95 and choose the default blend test, watch your temps and cpu-z volts, Prime will generate a lot of heat and if things get too toasty you may want to stop it. For cinema 4d users I will give you an animtion scene file that will take around 1.5 to 2 hours to render an animation, it will not generate so much heat but if you can finish the full render then you are almost sure your OC is stable ( but I could not guarantee that) even with Prime 95 things can be fine for 12 hours then the system may crash or my scene may render 600 frames then crash Again if Prime freezes or you crash to blue screen check the message and raise CPU volts or QPI-VTT by one setting and re test In general my settings may be a bit high as I think I have a below average chip and the 12 GB RAM is stressful, try lowering you QPI-VTT Note I use a Noctua D14 which is at the high end of the air coolers and get sub 80 C temps, if you are using something like a Fenrir you will likely get higher temps.

If temps worry you drop your overclock and voltages or "splash" out on a high end water cooling setup ( anywhere from £150 +)


Here Is the cinema 4d scene file for testing Overclock Test


Here is a BIOS template

I7 930
Gigabyte EX58A=UD3R Rev 1 Bios F5
12 GB Corsair 1600 Rated 9-9-9-04-2T 1.65V
Noctua NH-D14 with Noctua TIM
Xclio Windtunnel Case
650W Corsair CMPSU-650TX, single 12

CPU Clock Ratio – 21

Advanced CPU Features:-
CPU Clock Ratio - 21
Intel ® Turbo Boost Tech. -disabled
CPU Cores Enabled - enabled
CPU Multi-Threading - enabled
CPU Enhanced Halt (C1E) -enabled
C3/C6/C7 State Support -disabled
CPU Thermal Monitor - disabled
CPU EIST Function - enabled
Virtualization Technology - disabled
Bi-Directional PROCHOT - enabled

QPI Link Speed - 6.4 Ghz

Uncore & QPI Features:-
QPI Link Speed - X 36
Uncore Frequency - 3400 ( X 17)
Isochronous Support - Enabled

Base Clock (BCLK) Control -
BCLK Frequency (Mhz) - 191

Advanced Clock Control:-
Base Clock (BCLK) Control - Enabled
BCLK Frequency (Mhz) - 191
PCI Express Frequency (Mhz) - 101
C.I.A.2 - I cannot see this setiing
CPU Clock Drive - 800
PCI Express Clock Drive -900
CPU Clock Skew - 0
IOH Clock Skew - 0

Performance Enhance -
Extreme Memory Profile (X.M.P.) - Standard
System Memory Multiplier (SPD) - 8
DRAM Timing Schedule (SPD) - Auto

**The following 5 options need setting for each stick of ram**
CAS Latency Time - 9
tRCD - 9
tRP - 9
tRAS - 24
Command Rate (CMD) - 2

Load-Line Calibration - Level 2
CPU Vcore - 1.3875
QPI/Vtt Voltage - 1.335
IOH Core - 1.2
DRAM Voltage - 1.66

Advanced Voltage Control:-
Load-Line Calibration - Level 2
CPU Vcore - 1.3875
QPI/Vtt Voltage - 1.335
CPU PLL - Auto
PCIE - Auto
QPI PLL - Auto
IOH Core - Auto
ICH I/O - Auto
ICH Core - Auto
DRAM Voltage - 1.66


Here is a good article on thermal paste spreading ( god i need to get out more !!) note the section on HDT coolers such as the Fenrir http://benchmarkrevi...d=170&Itemid=38