Guide to setting "Per Core" Turbo overclock range of 4.5 to 4.8Ghz using individual "Per Core" Turbo Ratios
Disclaimer
If you attempt the overclock described below, it is entirely at your own risk. The author assumes no responsibility for any damage caused to your system, should you attempt it.
Author's Note
The following guide is written for an intended audience of new to moderate overclockers. I don't espouse to being an expert overclocker with the Sandy Bridge architecture but wanted to share my overclocking experiences and achievements, with the view that others may also be interested in this particular overclock.
Introduction
If you're a moderately cautious i7 2600K overclocker like myself and use a good air-cooling CPU heat-sink, you may have set your overclock to a maximum of 4.5Ghz across all cores, and are happy with that speed. Much of the 2600K overclocking community regard this Turbo of 4.5Ghz across all cores to be a safe 24x7 overclock for daily computer usage. At 4.5Ghz, CPU core temps generally stay below 80 degrees Celsius at full load, and is an easy overclock to achieve in the BIOS (most settings need only be set to default/Auto).
However, with some BIOS setting changes you can gain more performance out of your 2600K for apps that don't utilise all four cores, and without risking higher temps. Many applications do not utilise all four cores at one time, and that leaves extra headroom in your CPU.
What I've done is instead of setting my overclock to be 4.5Ghz across "All Cores" I've set a "Per Core" stepped overclock. Now when an app only uses one of the four CPU cores it automatically Turbos up to 4.8Ghz. When only 2 cores are used: 4.7Ghz, for 3 cores: 4.6Ghz, and for apps that use all four cores: the original base 4.5Ghz. In my testing, the temps and volts of the higher overclocks (when less than four cores are utilised) is less or equal to that when all four cores at 4.5Ghz are stressed at full load. That means bonus performance for us 4.5Ghz overclockers in day-to-day computer usage. Of course the CPU still idles at 1600Mhz, and only jumps to the specific stepped Turbo clock when the CPU is under load.
My computer
CPU: Intel i7 2600K
Cooler: Hyper 212+ (push & pull fans)
Motherboard: Asus P8P67 Pro (original B2 stepping)
BIOS version: 1305
RAM: 4x2GB Corsair DDR3-1600Mhz C9
Primary Hard Drive: Samsung SpinPoint F3 500GB HD502HJ
OS: Windows 7 64-bit
Graphics: nVidia GTX 460 1GB
The BIOS settings which worked for me for this Per Core overclock
Note: all BIOS settings are left at their default values unless specified below. I've added some comments about my findings during my testing:
AI Overclock Tuner: X.M.P (or Manual)
BCLK/PEG Frequency: 100.0
Turbo Ratio: By Per Core
1-Core Ratio Limit: 48
2-Core Ratio Limit: 47
3-Core Ratio Limit: 46
4-Core Ratio Limit: 45
Internal PLL Overvoltage: Disabled
Memory Frequency: (as per your RAM specification)
EPU Power Saving Mode: Enabled
EPU Setting: Auto
Load-Line Calibration: High (or Auto, however Auto will cause higher voltages and temps. I found any less than a setting of High for this "Per Core" overclock causes a BSOD during stress testing)
VRM Frequency: Auto (or 350)
VRM Spread Spectrum: Disabled
Phase Control: Standard (or Optimised)
CPU Voltage: Manual Mode (I found CPU volts and temps went too high during stress testing if this setting is set to Auto for this overclock. However a setting of Auto is fine if all cores are set to 4.5Ghz or below)
CPU Manual Voltage: 1.360 (At this voltage the actual voltage and watts used will still fluctuate depending on CPU load, as can be seen using Real Temp 1.37. While the CPU voltage of "1.360" works best for me , your CPU may require 1.365 or maybe more/less. If you get a Blue Screen of Death with error code 124, that typically means your CPU voltage is too low. Always watch your temps when trying a new CPU voltage. My own limit is to ensure the hottest core stays under 80 degrees Celcius, using air cooling with room temperate in the mid-20s Celcius. Each to their own liking, though.)
DRAM Voltage: (as per your RAM specification)
CPU Spread Spectrum: Disabled
CPU C1E: Enabled
CPU C3 Report: Enabled
CPU C6 Report: Enabled
Some Screenshots of my BIOS:
Screenshots of only one core being stressed:
Screenshots of all cores being stressed:
Tools I recommend to test and monitor your computer with these new settings:
Real Temp v3.67 (Shows core temps and real-time clock speeds. Tip: click the button on the top-right hand corner to cycle between time, volts, and watts)
Prime95
Windows Task Manager (Use the "Performance" tab to see each of the 4-cores/8-threads working.)
Cinebench 11.5 (Can test all cores or single core performance. Choose File > Advanced Benchmark)
AIDA64 Extreme Edition v1.60.1321 beta (I use Tools > "System Stability Test" > "Stress FPU" only, which causes the most heat, volts and CPU load of any stress test I've ever used. This is a commercial tool, but a trial version is available. Play with the new CPU Mask option to test only selected cores/threads. You'll need to convert a binary number of 8 character length (representing 8 threads) into hex. For example: To test the first and last threads of your 2600K CPU, the binary number 10000001 equates to 81 hex. See screenshot below )
That's all folks. Hope you've enjoyed my guide, and are able to gain extra performance out of your new i7 2600K CPU!
- HardLuck
Disclaimer
If you attempt the overclock described below, it is entirely at your own risk. The author assumes no responsibility for any damage caused to your system, should you attempt it.
Author's Note
The following guide is written for an intended audience of new to moderate overclockers. I don't espouse to being an expert overclocker with the Sandy Bridge architecture but wanted to share my overclocking experiences and achievements, with the view that others may also be interested in this particular overclock.
Introduction
If you're a moderately cautious i7 2600K overclocker like myself and use a good air-cooling CPU heat-sink, you may have set your overclock to a maximum of 4.5Ghz across all cores, and are happy with that speed. Much of the 2600K overclocking community regard this Turbo of 4.5Ghz across all cores to be a safe 24x7 overclock for daily computer usage. At 4.5Ghz, CPU core temps generally stay below 80 degrees Celsius at full load, and is an easy overclock to achieve in the BIOS (most settings need only be set to default/Auto).
However, with some BIOS setting changes you can gain more performance out of your 2600K for apps that don't utilise all four cores, and without risking higher temps. Many applications do not utilise all four cores at one time, and that leaves extra headroom in your CPU.
What I've done is instead of setting my overclock to be 4.5Ghz across "All Cores" I've set a "Per Core" stepped overclock. Now when an app only uses one of the four CPU cores it automatically Turbos up to 4.8Ghz. When only 2 cores are used: 4.7Ghz, for 3 cores: 4.6Ghz, and for apps that use all four cores: the original base 4.5Ghz. In my testing, the temps and volts of the higher overclocks (when less than four cores are utilised) is less or equal to that when all four cores at 4.5Ghz are stressed at full load. That means bonus performance for us 4.5Ghz overclockers in day-to-day computer usage. Of course the CPU still idles at 1600Mhz, and only jumps to the specific stepped Turbo clock when the CPU is under load.
My computer
CPU: Intel i7 2600K
Cooler: Hyper 212+ (push & pull fans)
Motherboard: Asus P8P67 Pro (original B2 stepping)
BIOS version: 1305
RAM: 4x2GB Corsair DDR3-1600Mhz C9
Primary Hard Drive: Samsung SpinPoint F3 500GB HD502HJ
OS: Windows 7 64-bit
Graphics: nVidia GTX 460 1GB
The BIOS settings which worked for me for this Per Core overclock
Note: all BIOS settings are left at their default values unless specified below. I've added some comments about my findings during my testing:
AI Overclock Tuner: X.M.P (or Manual)
BCLK/PEG Frequency: 100.0
Turbo Ratio: By Per Core
1-Core Ratio Limit: 48
2-Core Ratio Limit: 47
3-Core Ratio Limit: 46
4-Core Ratio Limit: 45
Internal PLL Overvoltage: Disabled
Memory Frequency: (as per your RAM specification)
EPU Power Saving Mode: Enabled
EPU Setting: Auto
Load-Line Calibration: High (or Auto, however Auto will cause higher voltages and temps. I found any less than a setting of High for this "Per Core" overclock causes a BSOD during stress testing)
VRM Frequency: Auto (or 350)
VRM Spread Spectrum: Disabled
Phase Control: Standard (or Optimised)
CPU Voltage: Manual Mode (I found CPU volts and temps went too high during stress testing if this setting is set to Auto for this overclock. However a setting of Auto is fine if all cores are set to 4.5Ghz or below)
CPU Manual Voltage: 1.360 (At this voltage the actual voltage and watts used will still fluctuate depending on CPU load, as can be seen using Real Temp 1.37. While the CPU voltage of "1.360" works best for me , your CPU may require 1.365 or maybe more/less. If you get a Blue Screen of Death with error code 124, that typically means your CPU voltage is too low. Always watch your temps when trying a new CPU voltage. My own limit is to ensure the hottest core stays under 80 degrees Celcius, using air cooling with room temperate in the mid-20s Celcius. Each to their own liking, though.)
DRAM Voltage: (as per your RAM specification)
CPU Spread Spectrum: Disabled
CPU C1E: Enabled
CPU C3 Report: Enabled
CPU C6 Report: Enabled
Some Screenshots of my BIOS:
Screenshots of only one core being stressed:
Screenshots of all cores being stressed:
Tools I recommend to test and monitor your computer with these new settings:
Real Temp v3.67 (Shows core temps and real-time clock speeds. Tip: click the button on the top-right hand corner to cycle between time, volts, and watts)
Prime95
Windows Task Manager (Use the "Performance" tab to see each of the 4-cores/8-threads working.)
Cinebench 11.5 (Can test all cores or single core performance. Choose File > Advanced Benchmark)
AIDA64 Extreme Edition v1.60.1321 beta (I use Tools > "System Stability Test" > "Stress FPU" only, which causes the most heat, volts and CPU load of any stress test I've ever used. This is a commercial tool, but a trial version is available. Play with the new CPU Mask option to test only selected cores/threads. You'll need to convert a binary number of 8 character length (representing 8 threads) into hex. For example: To test the first and last threads of your 2600K CPU, the binary number 10000001 equates to 81 hex. See screenshot below )
That's all folks. Hope you've enjoyed my guide, and are able to gain extra performance out of your new i7 2600K CPU!
- HardLuck
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