- Dec 27, 2009
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This guide was written based on Intel 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 AnandTech 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
(This is just my cooling solution but not recommendation! Click here to visit Cases & Cooling board for cooling advice.)
- Prolimatech Megashadow heatsink paired with 2x 2000rpm 19dB CoolerMaster SickelFlow Fan
- Arctic Silver 5 thermal compound
(Check 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.
[FONT="]LGA1156 CPU Documentation from Intel![/FONT]
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.
(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.
(p.s. 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
(LGA1156 CPU Maximum/absolute Maximum voltage by Intel: Vcore= 1.40/1.55, Vtt= 1.155/1.21, Vram= 1.575/1.65, PLL= 1.89/1.98) with PCH=1.10
For i5-750 ONLY: The following settings are good points to start with!
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.
*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 the system is stable, then it's the voltage you need to tweak. If the system is still unstable, 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= 1.40/1.55, Vtt= 1.155/1.21, Vram= 1.575/1.65, 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!
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 AnandTech 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
(This is just my cooling solution but not recommendation! Click here to visit Cases & Cooling board for cooling advice.)
- Prolimatech Megashadow heatsink paired with 2x 2000rpm 19dB CoolerMaster SickelFlow Fan
- Arctic Silver 5 thermal compound
(Check 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.
[FONT="]LGA1156 CPU Documentation from Intel![/FONT]
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.
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.
(p.s. 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
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= 1.40/1.55, Vtt= 1.155/1.21, Vram= 1.575/1.65, PLL= 1.89/1.98) with PCH=1.10
For i5-750 ONLY: The following settings are good points to start with!
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.
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 the system is stable, then it's the voltage you need to tweak. If the system is still unstable, 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= 1.40/1.55, Vtt= 1.155/1.21, Vram= 1.575/1.65, 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!
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