LGA 1156 Core i5 and Core i7 Overclocking guide

andy5174

Distinguished
Mar 3, 2009
2,452
0
19,860
49
This guide was written based on Core i5-750 CPU and Gigabyte GA-P55A-UD5 M/B!

This is for peoples who want to OC their PC but lazy to comprehend the basic knowledge of overclocking!
Thus, please don't criticize it for its unprofessional way of writing.

Warning: Overclocking DOES void the warranty. Neither TOM Hardware nor I will be responsible for any damage caused by overclocking!


0) HSF & Thermal grease

1) Decision making on the OC

2) How to start?

3) Voltages tweaking

4) Torture test


0) HSF & Thermal grease

- CoolerMaster Hyper 212 Plus has great performance for the cost.



- Prolimatech Megashadow is one of the top heatsinks which is paired with 2x 2000rpm 19dB CoolerMaster SickelFlow Fan here.




- Arctic Silver 5 is an excellent thermal grease with reasonable cost.



( Click here for the guide on thermal compound application! )


1) Decision making on the OC

What is the best OC?

Performance-efficiency wise

- The maximum OC that can be achieved near stock core voltage(1.20V shown on CPU-Z at 100% load).

- Power consumption increase is in LINEAR region! (The power increase in an exponential form after 3.6GHz -> Bad efficiency!)

For LGA1156 CPUs, 3.6GHz OC satisfies these two conditions.

Performance ONLY

The maximum frequency that can be achieved within the absolute maximum core voltage(1.55V for LGA1156 CPUs).

To be safe, you want to be within the maximum core voltage which is 1.40V for LGA1156 CPUs.

LGA1156 CPU Documentation from Intel!


2) How to start?

1. Enter the BIOS by pressing Delete key during POST(Power On Self Test)/Boot Screen.

2. Set BCLK, CPU multiplier/ratio, QPI Clock multiplier/ratio and Memory multiplier/ratio so that you can achieve the frequencies you want.

BCLK x CPU ratio = CPU frequency
BCLK x QPI ratio = QPI link speed -> set the ratio to the lowest possible value!
BCLK x Memory ratio = Memory frequency


My settings are:
CPU frequency: 180x20=3.6GHz
QPI link speed: 180x32=5.76GHz
Memory frequency:180x8=1440MHz
3. Manually set the memory timing according to the specification of your RAM, leaving everything unspecified as Auto.
(You have to set the DRAM Timing Selectable to Quick or Expert in order to do this in P55A-UD5!)

4. Disable the Turbo Boost Technology!

5. If it's impossible to get your system stable, disable C1E, C3/C6/C7 and EIST.

(C1E, C3/C6/C7 and EIST are power saving features and CPU will always run at highest clock when ALL of them are disabled.)

For i7-8xx CPUs, disable HT (Hyper Threading Technology) as well under this situation.


3) Voltages tweaking

Immensely useful information from Intel Datasheet! Give it a read before you move on, because it is going to help substantially in the following steps!


PCH: Intel P55 chipset voltage

- main I/O interface
- display connectivity
- audio feature
- power management
- manageability
- security
- Storage feature

It is pretty obvious that the higher the CPU frequency, the more frequent the I/O(input and output) and so the higher the power consumption of "main I/O interface". Hence, the PCH voltage needs to be increased based on the same current(P=VI). However, 1.10V should be sufficient for any OC achieved on air cooling.

PLL: Phase Locked Loop voltage

- Processor/IMC(Integrated Memory Controller)/other internal clocks
- Clock multiplying of processor is provided by an internal Phase Locked Loop

Generally, 1.8V(default value) and 1.9V for OC under 3.6GHz and 4.2GHz respectively.

Vtt

- L3 shared cache
- memory controller
- processor I/O power rail

Since memory controller frequency is dependent on BCLK, the higher the BCLK, the higher the Vtt required.
1. To achieve the absolute maximum OC, begin with applying the Maximum voltages(to be safe) or Absolute Maximum voltages(at your own risk) in BIOS.

(LGA1156 CPU Maximum/absolute Maximum voltage by Intel: Vcore= 1.40/[strike]1.55[/strike]1.40, Vtt= 1.155/[strike]1.21[/strike]1.40, Vram= 1.575/[strike]1.65[/strike]1.80, PLL= 1.89/1.98) with PCH=1.10

For i5-750 ONLY: The following settings are good points to start with!

In order to find out the minimum stable voltages, keep lowering the following voltages ONE at a time until your system becomes unstable.

(For example, varying ONLY the Vcore with all other voltages FIXED while trying to find out the minimum stable Vcore.)

The lower the voltages are, the cooler and healthier the CPU is!


3.6GHz:(24hrs Small FFTs test, 30hrs-2mins Large FFTs test and 14hrs-12mins Memtest86+ stable!)
Load-Line Calibration: Enabled (or Level2 for Gigabyte GA-P55A-UD5)
Vcore= 1.20V (CPU-Z idle)
QPI/Vtt/IMC= 1.14V
PCH= 1.10V
PLL= 1.80V
RAM= Specified voltage for your RAM

3.8GHz:
Load-Line Calibration: Disabled
Vcore= 1.264V (CPU-Z idle)
QPI/Vtt/IMC= 1.149V
PCH= 1.10V
PLL= 1.85V
RAM= Specified voltage for your RAM

4.0GHz:
Load-Line Calibration: Disabled
Vcore= 1.38V (CPU-Z idle)
QPI/Vtt/IMC= 1.25V <- Higher than absolute maximum Vtt
PCH= 1.10V
PLL= 1.88V
RAM= Specified voltage for your RAM

4.2GHz:
Load-Line Calibration: Disabled
Vcore= 1.43V (CPU-Z idle) <- Higher than maximum Vcore
QPI/Vtt/IMC= 1.30V <- Higher than absolute maximum Vtt
PCH= 1.10V
PLL= 1.90V
RAM= Specified voltage for your RAM
2. Set BCLK=210 with CPU Multiplier=20, (210,20), OR BCLK=200 with CPU Multiplier=21, (200,21), to make the CPU 4.2GHz which is the maximum on average chips.

3. Check for stability of your system:

- Stable: Jump to the next step, 4) Torture test, for thorough stability test. OR Set the BCLK and CPU Multiplier to (215,20 ) or (205,21) to get higher frequency.

- Unstable: Up the voltages at your own risk. OR Lower the BCLK and CPU Multiplier to (200,20) or (190,21) to be on the safe side. Keep repeating this until your PC is stable.


4) Torture test

1. Software required: CPU-Z, HWMonitor, Core Temp, Memtest86+ and Prime95

2. Run at least 12 hours Memtest86+ test and Large FFTs test of Prime95.

Monitor 100% load core temperatures

Make sure that your core temperatures are ALL within 72.7C which is the thermal specification from Intel!

p.s. Under 18C ambient temperature, my 100% load core temperatures are 48C-44C-44C-43C at 3.6GHz with the cooling solution specified earlier.
Prime95 Torture Test Options

- Small FFTs: CPU Stability test
- In-Place Large FFTs: Overall system(CPU/RAM Interface) stability test
- Blend: Memory stability test, NOT very useful! Use Memtest86+ instead

Click here for Prime95 instruction!
Go back to 3) Voltages tweaking and up the voltage a notch if it's not stable!

*Tip*: The best way to find out which voltage is causing the instability is setting the voltage that might be too low according to your 6th sense to its maximum value with ALL other voltages staying unchanged and see if the system is stable after this. If it is stable, then it's the voltage you need to tweak. If it is not, try tweaking another voltage in the same way.


For i5-750 ONLY: You might be extremely unlucky to have a chip that is much worse than the average with the stable voltages being much higher than those values given by me. What I would do under this situation is setting all the voltages to their maximum(NOT absolute maximum) values and lowering them ONE at a time until you get instability. However, try it again with C1E, C3/C6/C7 and EIST disabled before doing so.
(p.s. Maximum/absolute Maximum voltage by Intel: Vcore= 1.40/[strike]1.55[/strike]1.40, Vtt= 1.155/[strike]1.21[/strike]1.40, Vram= 1.575/[strike]1.65[/strike]1.80, PLL= 1.89/1.98)


N.B. Any OC below 3.8GHz should be very easy and don't go above that if either of your core temperatures or core voltage is already near its maximum specification at the point.


Good luck!

UPDATES:
28June10:
- Absolute Maximum Vcore, Vtt, and Vram change in latest Intel datasheet revision!
 

Lutfij

Titan
Moderator
Took me a while to find this post and report it to RANDOMIZER (about a month ago) :) good to know that this guide is doing its part...though I'm working on a 1366 guide for overclocking.

Cheers
 

omgitswes

Distinguished
Dec 9, 2010
44
0
18,530
0
Just wondering, the steps you posted for i5 750 only. Could those also be applied for the 760 too? Or are they completely different chips?
 

Explo

Distinguished
Sep 16, 2010
33
0
18,530
0
Anyone know how loud those CM SickleFlow fans really are? Hard to believe 19db... and is there any info on how much benefit two of them gives over one?
 

Lutfij

Titan
Moderator
a minimal amount maybe a degree or two(for the CM Hyper 212+ ofcourse) there's not much distance for the air to travel from fan 1 to fan 2...you could try and get scythe's to work on them, they're really quiet and efficient.
 

andy5174

Distinguished
Mar 3, 2009
2,452
0
19,860
49


Update: The SickleFlows become very quiet after I taking out the 2nd CPU fan that is very close to the rear case fan.
 

9000PC

Distinguished
Jul 9, 2008
31
0
18,530
0
"3) Voltages tweaking

Quote :

Immensely useful information from Intel Datasheet! Give it a read before you move on, because it is going to help substantially in the following steps!

...........


PLL: Phase Locked Loop voltage

- Processor/IMC(Integrated Memory Controller)/other internal clocks
- Clock multiplying of processor is provided by an internal Phase Locked Loop

Generally, 1.8V(default value) and 1.9V for OC under 3.6GHz and 4.2GHz respectively.

I have an CI7 920 @3.2 on a Asus P6T (X58) can I use that info also or that is only for mobos with Intel P55?
 

andy5174

Distinguished
Mar 3, 2009
2,452
0
19,860
49
You can also turn off LLC for 3.6GHz or less. I chose to turn it on as there were less ripple in voltage by doing so. However, it would be safer to turn off LLC (which disable voltage overshoot protection) since LGA1156's voltage increases rapidly above 3.6GHz and overshoot voltage could easily exceed the specified safe zone.

For more information regarding Load-line Calibration,
http://www.anandtech.com/show/2404/5
 

joraph

Distinguished
Sep 26, 2011
29
0
18,530
0
I thought you need a liquid cooling system to do overclocking... Is the CoolerMaster Hyper 212 Plus better than the any liguid cooling system... I really confus right now.
 

monographix

Distinguished
Jan 11, 2010
19
0
18,510
0
Great information. thumbs up and appreciation for putting it together for us.
Questions :

1. I am thinking of having my ECS P55H-A board running at 160 Mhz BClock continuously. I guess that would be maybe about 1.30 Vcore ? (or possible maybe with less Vcore?) Are those two figures considered, if we can say that, safe enough for an average P55 board to run permanently like that without any hardware damage risks? (i just read of some P55 board that burnt by running 24/7 at 1.36 Vcore and probably ~ 190-200 Bclock)

2. I think that for 1156 CPUs regarding QPI

BCLK x CPU ratio = CPU frequency
BCLK x QPI ratio = QPI link speed -> set the ratio to the lowest possible value!
BCLK x Memory ratio = Memory frequency
You don't have the option to change QPI ratio, somehow is lock-linked to CPU ratio or is just locked to a single default value or something ? some help here , i might be confusing it with something else ?

the calculator here http://icrontic.com/files/apps/nehalem-calc/ indicates i think that as also the fact that i cant find i think a QPI modification option in my P55H-A bios, (pics & info here : http://www.hardwaresecrets.com/article/ECS-P55H-A-Black-Series-Motherboard/803/5 . Maybe is the "DOC" ? ECS calls it "Dynamic Over Clock function for allowing user set a CPU base clock" ...)

3. Is it possible to set-up an OC in a way though that when the CPU is iddle or under light load to operate in slower Ghz ? (would that be maybe disable all power saving features but EIST ?and would that be effective in keeping the CPU cooler and consume less power?)
 

ASK THE COMMUNITY

TRENDING THREADS