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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
  • 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.)
Choosing the right processor

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.
  1. Enter BIOS.
  2. 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"
  3. Reboot.
If it was successful, your processor should have a new name; ending in either x3, x4, or x6. Though naming is not always consistent on some boards. Congratulations, because you probably just unlocked your processor.

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.
  1. 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.*
  2. Is ACC or NCC enabled? For Asus/Gigabyte motherboards, how about "Unleashing" and "EC Firmware"?
  3. Did you incrementally increase Vcore from 1.325 to 1.4v?
  4. Did you incrementally increase Vcpu-nb from 1.2 to 1.35v after trying to increase Vcore?
The voltage boosts may be needed when making the fourth core stable enough to boot into windows.

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.
 

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Might want to re-title your thread so that people understand that "unlocking" an extra core isn't guaranteed.

Even when reading other posts, some individuals jump to assume that it's ALWAYS possible.


Very good guide otherwise, but the suggested motherboard section is kind of weird to me. Why would MSI or any other company's board not work as well, even if it has the SB710 or 750? I understand you have listed 2 boards that people always recommend, but I would shy away from telling people to stay away from certain brands, especially if all those boards offer the same SB.

I mean, I would never buy MSI again anyway, but I just thought I would throw that out there as a suggestion for a guide. Good work my friend! R+
 

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I guess I included the motherboard section because some motherboards are just known to work over others.

There are lists spread out throughout multiple forums which discusses 4th core unlocking success. I am using my own personal experience and the data from those lists to reach a conclusion.

I guess I made this guide to make sure people who intend to unlock disabled cores have the highest possible success rate. If it means buying one brand of motherboards over another brands, then so be it. I didn't mean to step on any manufacturer's tails or create controversy, but just mainly to increase everyone's core unlocking chances.

Thanks for your words of encouragement. Hope this guide helps.
 

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I think it needs better formatting and maybe a picture or two wouldn't hurt. Also why are those the only "preferred" unlocking boards? I know all DFI boards can unlock along with new bioses from MSI and Asus. But nonetheless, good guide.
 
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THESE ARE NOT DEFECTIVE CORES. They are usually disabled cause the processor did not perform well. I am sure the DEFECTIVE word will cause a debate. It doesn't necessarily mean they are defective. On some chips you can enable them and they overclock nice and stable.
 

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nice way to start a guide. hope to see some more facts added along the way.
 

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I will get to making formatting changes very soon.

I will also add DFI under the list of supported brands.

While it is alot of work, I hope in the end list all SB710 and SB750 motherboards currently on the market and perhaps link a CPU-Z valiadation of some sort. Someone in the "AMD MOBO" section of this board has already started on this. I hope to credit him and at least link to the post, if not copy it, to this guide.
 

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I've got a 720BE with the perfect mobo for unlocking, yet I need to apply lots of voltage and underclock to be able to boot into windows
 

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Quote:

Originally Posted by jimibgood View Post
THESE ARE NOT DEFECTIVE CORES. They are usually disabled cause the processor did not perform well. I am sure the DEFECTIVE word will cause a debate. It doesn't necessarily mean they are defective. On some chips you can enable them and they overclock nice and stable.
You are wrong. Some are actually defective, whilst others are perfectly fine quad cores being locked to satisfy demand. The guide explained it perfectly. Don't post worthless information IN CAPS like that giving someone false hope.
 
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Originally Posted by Dopamin3 View Post
You are wrong. Some are actually defective, whilst others are perfectly fine quad cores being locked to satisfy demand. The guide explained it perfectly. Don't post worthless information IN CAPS like that giving someone false hope.

It is terminology and the key word is "some". The processors did not perform up to specs. That's why they disabled the cores. It wasn't 1 core that made the chip not pass. Disabling 1 core made it a tri-core that passed the 720 minimum specs. It does not mean they are defective but we are talking in words. If they work, they are not defective. Plain and simple.

Intel did something similar years ago. At this point, I am not saying they are or are not defective. Its an interpretation but if you unlock the 4th core and it works does that mean it was defective? Nope! when they tested them at AMD and they did not pass specs, they disable a core thus making it a tri-core. In most cases the 4th core works. Again is it defective???? Nope, maybe it wouldn't clock at the spec core frequency, but when they lock the 4th core it did. So saying this, unlocking the 4th works at least 90% of the time if not more.

It really is not worthless information. I fully read the explanation years ago when AMD first did this and someone "labelled" them as defective but as you attest, some are not defective!

I got an unlucky 940. Mine barely is stable at 3.7GHz(while others get higher). I cannot get higher but the chip passed the minimum spec for 940 so they released it as a 940. Chips that do not pass min requirements as advertised are thrown as a 720 tri core with 1 core locked. This does not mean the core is defective, it means the chip did not pass min req. advertised frequency. Again, the 4th core works and it is not defective.

Anytime you disable a core, you can clock the chip much higher. I locked 2 cores on my 940 and clocked it to 3.91GHz stable. I guess I have a 550 now? LOL but my 4 cores are not defective.

With all this in mind, someone at AMD made a great strategy. Instead of wasting those chips, they did what was explained above and saved the company a lot of money or maybe I should say made the company a lot more $ with these subpar chips. Some actually overclock very nicely and hang with the 940 with the 4th core enabled.

If they would have released these chips that were even close to 940 specs, they would have had a reputation nightmare. Making them 720's was very smart.

They also did this with the original Phenoms.

In closing you are WRONG.
 

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Quote:

Originally Posted by jimibgood View Post
It is terminology and the key word is "some". The processors did not perform up to specs. That's why they disabled the cores. It wasn't 1 core that made the chip not pass. Disabling 1 core made it a tri-core that passed the 720 minimum specs. It does not mean they are defective but we are talking in words. If they work, they are not defective. Plain and simple.

Intel did something similar years ago. At this point, I am not saying they are or are not defective. Its an interpretation but if you unlock the 4th core and it works does that mean it was defective? Nope! when they tested them at AMD and they did not pass specs, they disable a core thus making it a tri-core. In most cases the 4th core works. Again is it defective???? Nope, maybe it wouldn't clock at the spec core frequency, but when they lock the 4th core it did. So saying this, unlocking the 4th works at least 90% of the time if not more.

It really is not worthless information. I fully read the explanation years ago when AMD first did this and someone "labelled" them as defective but as you attest, some are not defective!

I got an unlucky 940. Mine barely is stable at 3.7GHz(while others get higher). I cannot get higher but the chip passed the minimum spec for 940 so they released it as a 940. Chips that do not pass min requirements as advertised are thrown as a 720 tri core with 1 core locked. This does not mean the core is defective, it means the chip did not pass min req. advertised frequency. Again, the 4th core works and it is not defective.

Anytime you disable a core, you can clock the chip much higher. I locked 2 cores on my 940 and clocked it to 3.91GHz stable. I guess I have a 550 now? LOL but my 4 cores are not defective.

With all this in mind, someone at AMD made a great strategy. Instead of wasting those chips, they did what was explained above and saved the company a lot of money or maybe I should say made the company a lot more $ with these subpar chips. Some actually overclock very nicely and hang with the 940 with the 4th core enabled.

In closing you are WRONG.

In my background section, I think I explained things broad enough so that both you and Dopamine are correct. Let us leave it at that. SOME processors have defective cores, and others have cores which were disabled to meet market demands. Regardless, they were disabled for a reason. Broadly speaking, they did not meet AMD's quality control specifications for reasons unknown to the public. Since we have no method of determining which chips have defective cores, I will continue to use the term "defective" to encompass the disabled cores as well.
 

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it is a nice guide.
and to jimibgood, your tone is totally unnecessary
please read this
Usage of Overclock.net is contingent on the following:

* You positively contribute to the forum and its membership
* You aid in maintaining a friendly and professional atmosphere
* You live within the rules and regulations set out by Overclock.net
* You respect the site, its management and its members
* You do not troll or attempt to stir up trouble within the community

as dopamin3 said "some" that's that move along, quit trolling and disrespecting members.
 

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Quote:

Originally Posted by 0m3g4 View Post
it is a nice guide.
and to jimibgood, your tone is totally unnecessary
please read this
Usage of Overclock.net is contingent on the following:

* You positively contribute to the forum and its membership
* You aid in maintaining a friendly and professional atmosphere
* You live within the rules and regulations set out by Overclock.net
* You respect the site, its management and its members
* You do not troll or attempt to stir up trouble within the community

as dopamin3 said "some" that's that move along, quit trolling and disrespecting members.

Nothing disrespectful and its your interpretation of "the tone" and this is not trolling to stir anything up. Just responding and adding pertinent information to those who do not know the marketing strategy that AMD made in reference to the 720BE just as they did with the original Phenom release(defective core). Some use the term defective but in actuality, they are not as seen by the unlocking of the 4th core and getting overclocks in line with the 940. There was no explanation of the units that could not "unlock" the 4th core but some still refer to the 4th core as defective.

I have been following this for years and the OP made a nice observation. The term "defective" is not true in most cases but may be on those stingy units that have a locked core.

Look at it this way. In most probability, it is not 1 specific core causing this. It most likely is all 4 cores enabled making it a unstable chip. Disable 1 core and Bingo! a stable 720 tri core. Seeing this, it looks like AMD plain locked 1 core on those units.This is a true and potential possibility and that would not be the definition of a "defective" core.
 

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Quote:

Originally Posted by jimibgood View Post
Nothing disrespectful and its your interpretation of "the tone" and this is not trolling to stir anything up. Just responding and adding pertinent information to those who do not know the marketing strategy that AMD made in reference to the 720BE just as they did with the original Phenom release(defective core). Some use the term defective but in actuality, they are not as seen by the unlocking of the 4th core and getting overclocks in line with the 940. There was no explanation of the units that could not "unlock" the 4th core but some still refer to the 4th core as defective.

I have been following this for years and the OP made a nice observation. The term "defective" is not true in most cases but may be on those stingy units that have a locked core.

Look at it this way. In most probability, it is not 1 specific core causing this. It most likely is all 4 cores enabled making it a unstable chip. Disable 1 core and Bingo! a stable 720 tri core. Seeing this, it looks like AMD plain locked 1 core on those units.This is a true and potential possibility and that would not be the definition of a "defective" core.
Why are you still arguing about this ? Stop being so Pedantic about Semantics.
 

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Quote:

Originally Posted by sarngate View Post
Why are you still arguing about this ? Stop being so Pedantic about Semantics.

Please be respectful about my definition of "defective". I was not disrespectful to you. I was just explaining that some do not view these cores as defective. Many have the same feeling and that is why this is called a forum. It is in my rights to comment about the subject. AMD says these cores are not defective. They do not pass quality specs. Unless proved otherwise, I label them as disabled cores for the facts AMD has stated and described above.
 

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ahaha that just made me laugh, also, for someone to even make this a guide is what puzzled me..there isnt really anything to learn or being taught in this thread..but this IS a great informative post for those that keeps on googling "amd phenom II unlock"; this is one post for all information. =] and theres quite a few of us using gigabyte boards in the 700 x3 thread. i was the first one i believe and it unlocks perfectly..
 

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Step 1: Ensure compatible motherboard.
Step 2: Ensure compatible bios version.
Step 3: Enable ACC.
Step 4: Party down.

There's my guide

I bought a 3.1Ghz Dual Core CPU @ 1.312v.
Running a 3.5Ghz Quad Core CPU @ 1.296v.
The temperatures blow my mind, too... 40C under Prime load !=O!
And that's just the beginning... Mua ha ha.
 

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raxen, you definitely need to add this to your guide, as it is not complete. On some boards including the Gigabyte MA790XT-UD4P, you need to set the EC Firmware to Hybrid. I thought I had a "dud" chip, when I first tried unlocking the 4th core by just setting ACC to Auto. Once I changed EC Firmware to Hybrid, and then change ACC to Auto, I was able to unlock the 4th core.

Also you should make a list of MoBos and bios that work. The Gigabyte MA790XT-UD4P with the F4G bios revision works.
 

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Quote:

Originally Posted by Broodman View Post
raxen, you definitely need to add this to your guide, as it is not complete. On some boards including the Gigabyte MA790XT-UD4P, you need to set the EC Firmware to Hybrid. I thought I had a "dud" chip, when I first tried unlocking the 4th core by just setting ACC to Auto. Once I changed EC Firmware to Hybrid, and then change ACC to Auto, I was able to unlock the 4th core.

Also you should make a list of MoBos and bios that work. The Gigabyte MA790XT-UD4P with the F4G bios revision works.
Duly noted and added to the guide. Mobo list will come later.
 
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