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AMD K10.5* Core & Cache Unlocking Guide
*K10.5 includes Athlon II, Phenom II, & Sempron II CPU's
Introduction
Core unlocking of AMD chips has been a very hot topic of discussion. The possibility of spending a mere $100 dollars for a Phenom II X2/X3 chip and unlocking the disabled cores to yield a $200 dollar X4 chip is exactly like the goal of every overclocker around - spend the least amount of money possible and get the most bang for your buck. I have written this guide to consolidate the information surrounding core unlocking, and to answer any questions you guys might have.
Remember, core unlocking is NOT GUARANTEED. However, the aim of this guide is to help everyone increase their chances of successful unlocks.
Background
The current K10.5 design is an evolution of the older AMD Phenom Design (K10) which had 1 piece of silicon being made producing 4 Cores on this one die, and then disabling or lazer cutting (which has been done by GPU's in the past) to make lower end chips because 1 or more of the cores did not function properly. Or their was more market demand for lesser variants of the same design. AMD's "True Quad Core" was a large marketing effort by them to combat Intel's approach which was to put 2 Dual Core dies together on one chip and bridge them together to make a Quad Core CPU.
Like all manufacturing processes, chip fabrication is no different. There are always parts which don’t make the quality cut. In the case of the Phenom II Quad cores, these parts may have defective cores or cache. Rather than throwing these defective Quad cores out, AMD decided to repackage these chips as Dual cores or Tri core processors or disable the cache and call them Athlon II. It was a win-win scenario for AMD. They would sell these processors at a cheaper price to recover costs and also minimize wasted time and production materials. As in business it's always more costly to sit on excess stock or defective units than it is to either throw them away or repackage and sell them.
When the Phenom II X3 720BE was released, it was highly popular among mainstream enthusiasts. Like all BE processors, the 720BE had an unlocked multiplier, which made overclocking it an extremely simple process. Furthermore, it was priced competitively against Intel’s Core2Duo E6xxx series, but performance actually rivaled the E8xxx series. Why would you pay Intel for a Dual core when you can get a Tri core from AMD that had the same performance clock for clock but an easier time overclocking?
However, the surge in demand for 720BE processors started when a Korean overclocker first discovered that the “defective†core could be unlocked. He used a motherboard with a SB750 southbridge which supported Advanced Clock Calibration (ACC): the Biostar TA790GX. Soon after, others reported similar success in unlocking the 720BE. This phenomenon eventually extended to include X3 710 and X2 550BE processors as well.
Unoffically, AMD reported record sales of X3 processors, no doubt, in part due to fourth core unlocking. Many believe that the increasing rates of successful unlocks is due to AMD purposedly binning perfectly working X4s as X3s to sastify market demands. What does this mean for you? Your chances of getting an unlockable X3 chip just got better.
Quick overview of parts needed
Choose your CPU from the following models. Even if you don’t end up unlocking the 4th core by following this guide, you can’t go wrong because you still would have gotten the best bang for your buck. These chips are proven overclockers.
If you insist on picking a particular stepping, you should check out what your stepping is. If you do not know how to figure out what stepping or revision you have, see this thread:
How to check the Revision or Stepping of your AMD CPU.
Choosing the right motherboard:
In general, make sure the motherboard has a SB710 or SB750 southbridge and ACC is supported before purchasing. However, there are exceptions, as some motherboard manufacturers have disabled ACC core unlocking features. Rumors were floating around that AMD discouraged theO unlocking of cores. Hopefully the following list will clarify which motherboards work and which ones don't. Keep in mind that the BIOS revision plays an important role in unlocking. For example, with the Biostar TA790GX 128M motherboard, only 78DEA113 bios unlocks cores. The 78DEA525 bios DOES NOT UNLOCK ANYTHING.
Special Note about Asus Motherboards
UPDATE 22/8/09: Asus has released new bioses for their M4Axx line which addresses all previous unlocking problems. Make sure you update your bios to the most recent one before attempting to unlock.
The Unlocking Process
In terms of unlocking your “defective†cores, the process is actually very simple.
Once you are in Windows, or any other OS that you use, you should begin stability testing for your unlocked processor. I highly suggest the use of Prime95 "Blend Test" for 24 hours to ensure stability before overclocking.
I see X4, but I only have 2 cores!?!?
Some users have been reported seeing the "X4" designation, but no unlocked cores when verifying through CPU-Z. Please ensure that you have set Windows to use all 4 cores by going to "msconfig --> Boot --> Advanced Options --> Number of Processors." If you still don't see unlocked cores, then most likely that your disabled cores are defective.
HELP!! My computer can't POST!!
If your computer didn't POST, don’t despair. Here's a list of things you should verify and try, one after the other.
If your computer still doesn't POST, then most likely your disabled cores are defective. In general, the unlocking process is really that simple. There are no hidden options or tricks.
Unlocking disabled cores should be seen as a bonus, and not a feature.
![]()
An unlocked AMD X3 720BE to X4 using an Asus M4A78-E with 1204 BIOS. Vcore = 1.35v. Vcpu-nb = 1.25v. ]CPU-Z Validation.
Consequences of Unlocking
While some of you will be lucky enough to see the "X4" designation during POST, not all of you will be able to boot into Windows. A simple Vcore/Vcpu-nb boost may help stabilize the unlocked cores, but ultimately the cpu may remain unstable and crash later on. Unfortunately, your disabled cores are most likely defective.
For those who can unlock and pass any stability test you can throw at the computer, congratulations. However, you may have already noticed that you can no longer monitor your cpu core temperatures. Fortunately, most motherboards have a cpu temperature sensor located in the cpu socket area. It is up to you to find out how closely this temperature reading relates to the actual cpu core temperatures.
To do so, revert back to a locked X2/X3 state and download HWMonitor. Depending on your motherboard, the cpu socket temperature sensor can be TMPIN0, TMPIN1, or TMPIN2. Next, observe how closely TMPIN0 or TMPIN1 or TMPIN2 relates to core temperatures at 100% load. This will tell you your approximate temperatures when unlocked. You can use this reading as a rough estimate of your core temperatures.
You may also notice that your computer runs hotter after unlocking. This is perfectly normal, as you've got an extra core or two generating heat. As a result, for those who plan on unlocking, get the best cooler you can possibly afford. I would suggest looking at the Air Cooling Guide - Questions Answered Here
This way you can have help choosing the best setup for your budget & your system.
Conclusion
Good luck with Phenom II core unlocking. The take-home point however, is the following:
Not all CPU's will unlock. And sometimes not all CPU's will unlock on all boards. This is all subjective just like overclocking. And it's not a feature of the CPU but a bonus from either being lucky or doing your research.
I will continue to make changes and edit this thread as needed. I hope to generate a full list of supported motherboards in the end.
Last Thread Info Update: Thursday August 19th, 2010.
*K10.5 includes Athlon II, Phenom II, & Sempron II CPU's
Introduction
Core unlocking of AMD chips has been a very hot topic of discussion. The possibility of spending a mere $100 dollars for a Phenom II X2/X3 chip and unlocking the disabled cores to yield a $200 dollar X4 chip is exactly like the goal of every overclocker around - spend the least amount of money possible and get the most bang for your buck. I have written this guide to consolidate the information surrounding core unlocking, and to answer any questions you guys might have.
Remember, core unlocking is NOT GUARANTEED. However, the aim of this guide is to help everyone increase their chances of successful unlocks.
Background
The current K10.5 design is an evolution of the older AMD Phenom Design (K10) which had 1 piece of silicon being made producing 4 Cores on this one die, and then disabling or lazer cutting (which has been done by GPU's in the past) to make lower end chips because 1 or more of the cores did not function properly. Or their was more market demand for lesser variants of the same design. AMD's "True Quad Core" was a large marketing effort by them to combat Intel's approach which was to put 2 Dual Core dies together on one chip and bridge them together to make a Quad Core CPU.
Like all manufacturing processes, chip fabrication is no different. There are always parts which don’t make the quality cut. In the case of the Phenom II Quad cores, these parts may have defective cores or cache. Rather than throwing these defective Quad cores out, AMD decided to repackage these chips as Dual cores or Tri core processors or disable the cache and call them Athlon II. It was a win-win scenario for AMD. They would sell these processors at a cheaper price to recover costs and also minimize wasted time and production materials. As in business it's always more costly to sit on excess stock or defective units than it is to either throw them away or repackage and sell them.
When the Phenom II X3 720BE was released, it was highly popular among mainstream enthusiasts. Like all BE processors, the 720BE had an unlocked multiplier, which made overclocking it an extremely simple process. Furthermore, it was priced competitively against Intel’s Core2Duo E6xxx series, but performance actually rivaled the E8xxx series. Why would you pay Intel for a Dual core when you can get a Tri core from AMD that had the same performance clock for clock but an easier time overclocking?
However, the surge in demand for 720BE processors started when a Korean overclocker first discovered that the “defective†core could be unlocked. He used a motherboard with a SB750 southbridge which supported Advanced Clock Calibration (ACC): the Biostar TA790GX. Soon after, others reported similar success in unlocking the 720BE. This phenomenon eventually extended to include X3 710 and X2 550BE processors as well.
Unoffically, AMD reported record sales of X3 processors, no doubt, in part due to fourth core unlocking. Many believe that the increasing rates of successful unlocks is due to AMD purposedly binning perfectly working X4s as X3s to sastify market demands. What does this mean for you? Your chances of getting an unlockable X3 chip just got better.
Quick overview of parts needed
- AMD Phenom II x3, Phenom II x4 (with a T at the end of their model number like the 960T), Athlon II (with a cacad stepping code), or AMD Phenom II x2
- Motherboard with:
- Advanced Clock Calibration (ACC; present on the SB710 & SB750 motherboard.)
- Core Unlocker, Turbo Unlocker (or any other name given to motherboards by the maker to replace ACC which isn't present in the SB800 Series.)
- NVCC (Present on some nForce 7 series and all nForce 9 Series motherboard.)
- A little bit of luck (arguably the most important part.)
Choose your CPU from the following models. Even if you don’t end up unlocking the 4th core by following this guide, you can’t go wrong because you still would have gotten the best bang for your buck. These chips are proven overclockers.
- AMD Phenom II x2
- AMD Athlon II x3
- AMD Athlon II x4
- AMD Phenom II x3
- AMD Phenom II x4 xxxT
If you insist on picking a particular stepping, you should check out what your stepping is. If you do not know how to figure out what stepping or revision you have, see this thread:
How to check the Revision or Stepping of your AMD CPU.
Choosing the right motherboard:
In general, make sure the motherboard has a SB710 or SB750 southbridge and ACC is supported before purchasing. However, there are exceptions, as some motherboard manufacturers have disabled ACC core unlocking features. Rumors were floating around that AMD discouraged theO unlocking of cores. Hopefully the following list will clarify which motherboards work and which ones don't. Keep in mind that the BIOS revision plays an important role in unlocking. For example, with the Biostar TA790GX 128M motherboard, only 78DEA113 bios unlocks cores. The 78DEA525 bios DOES NOT UNLOCK ANYTHING.
Special Note about Asus Motherboards
UPDATE 22/8/09: Asus has released new bioses for their M4Axx line which addresses all previous unlocking problems. Make sure you update your bios to the most recent one before attempting to unlock.
The Unlocking Process
In terms of unlocking your “defective†cores, the process is actually very simple.
- Enter BIOS.
- Set Automatic Clock Calibration (ACC) or Nvidia Core Calibration (NCC) to AUTO.
CRUCIAL step for Asus and Gigabyte owners : Enable "Unleashing" or change "EC Firmware" mode to "Hybrid" - Reboot.
Once you are in Windows, or any other OS that you use, you should begin stability testing for your unlocked processor. I highly suggest the use of Prime95 "Blend Test" for 24 hours to ensure stability before overclocking.
I see X4, but I only have 2 cores!?!?
Some users have been reported seeing the "X4" designation, but no unlocked cores when verifying through CPU-Z. Please ensure that you have set Windows to use all 4 cores by going to "msconfig --> Boot --> Advanced Options --> Number of Processors." If you still don't see unlocked cores, then most likely that your disabled cores are defective.
HELP!! My computer can't POST!!
If your computer didn't POST, don’t despair. Here's a list of things you should verify and try, one after the other.
- Do you have the proper BIOS version installed?
*For those with Asus motherboards, please update your bios to the latest version. It fixes significant problems encountered with unlocking.* - Is ACC or NCC enabled? For Asus/Gigabyte motherboards, how about "Unleashing" and "EC Firmware"?
- Did you incrementally increase Vcore from 1.325 to 1.4v?
- Did you incrementally increase Vcpu-nb from 1.2 to 1.35v after trying to increase Vcore?
If your computer still doesn't POST, then most likely your disabled cores are defective. In general, the unlocking process is really that simple. There are no hidden options or tricks.
Unlocking disabled cores should be seen as a bonus, and not a feature.
An unlocked AMD X3 720BE to X4 using an Asus M4A78-E with 1204 BIOS. Vcore = 1.35v. Vcpu-nb = 1.25v. ]CPU-Z Validation.
Consequences of Unlocking
While some of you will be lucky enough to see the "X4" designation during POST, not all of you will be able to boot into Windows. A simple Vcore/Vcpu-nb boost may help stabilize the unlocked cores, but ultimately the cpu may remain unstable and crash later on. Unfortunately, your disabled cores are most likely defective.
For those who can unlock and pass any stability test you can throw at the computer, congratulations. However, you may have already noticed that you can no longer monitor your cpu core temperatures. Fortunately, most motherboards have a cpu temperature sensor located in the cpu socket area. It is up to you to find out how closely this temperature reading relates to the actual cpu core temperatures.
To do so, revert back to a locked X2/X3 state and download HWMonitor. Depending on your motherboard, the cpu socket temperature sensor can be TMPIN0, TMPIN1, or TMPIN2. Next, observe how closely TMPIN0 or TMPIN1 or TMPIN2 relates to core temperatures at 100% load. This will tell you your approximate temperatures when unlocked. You can use this reading as a rough estimate of your core temperatures.
You may also notice that your computer runs hotter after unlocking. This is perfectly normal, as you've got an extra core or two generating heat. As a result, for those who plan on unlocking, get the best cooler you can possibly afford. I would suggest looking at the Air Cooling Guide - Questions Answered Here
This way you can have help choosing the best setup for your budget & your system.
Conclusion
Good luck with Phenom II core unlocking. The take-home point however, is the following:
Not all CPU's will unlock. And sometimes not all CPU's will unlock on all boards. This is all subjective just like overclocking. And it's not a feature of the CPU but a bonus from either being lucky or doing your research.
I will continue to make changes and edit this thread as needed. I hope to generate a full list of supported motherboards in the end.
Last Thread Info Update: Thursday August 19th, 2010.
