raxen

AMD PHENOM II CORE UNLOCKING GUIDE*


*As of 12/11/09, some Athlon II processors also apply.

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.

DISCLAIMER: I am no means an expert. I’m just extremely interested in the subject. My experience is limited to the X2 550BE and the X3 720BE. As a result, for the gurus out there, I welcome you to chime in and correct me. I will keep this post updated with new information and corrections.

Background
The current Phenom II architecture is very unique, and is AMD’s answer to Intel’s Core2Duo and Core2Quad series. Unlike the Core2Quad, which is essentially two Core2Duo’s bridged together, AMD’s Phenom II is a chip with four individual cores.

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. It was a win-win scenario for AMD. They would sell these processors at a cheaper price to recover costs and also minimize wasted parts.

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?

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

1. AMD Phenom II processors – Codename Heka (Tri-cores) or Callisto (Dual-cores).
   **As of 12/11/09, some Athlon II processors DO APPLY.
2. Motherboard with ACC support (SB710 or SB750 southbridge) or NCC (Nvidia’s answer to ACC) AND supports core unlocking. More on specific boards and manufacturers later.
3. A little bit of luck

Choosing the right processor
As previously mentioned, all of AMD’s Phenom II processors contain four cores. X2 processors are X4 processors with two disabled cores, and X3 processors are X4 processors with one disabled core. There is a possibility of unlocking those disabled cores using ACC and the right motherboard.

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 the two links below:

Choosing the right motherboard:
In my opinion, this is the determining factor of whether you can unlock your processor. My personal motherboard of choice is the Biostar TA790GX 128M with 78DEA113 BIOS. I have successfully unlocked my X2 550BE and X3 720BE with this board. Other popular choices include the Gigabyte line of products listed below.

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 the 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 Motherboard List (Ongoing Work):
CONTRIBUTIONS WELCOME!! - If you see your mobo not on the list but you have successfully unlocked, post a screenshot of CPU-Z showing 4 cores and the mobo + bios revision like the sample below and I'll add it to the list.
This list is NOT COMPLETE WHATSOEVER. If your motherboard is not on the list, don't assume it won't work. Give things a try with the directions below.

Asus *See Special Note Above*
GeForce 8300
M4N78 Pro - 1004 Official Bios - SUCCESS!! *Thanks Henderson*
nForce 980a SLI
M4N82 Deluxe - 0906 Official Bios - SUCCESS!! Pending screenshot *Thanks biaxident*
770G/SB710
M4A77TD PRO - 1007 Official Bios - SUCCESS!! *Thanks flex0r*
785G/SB710
M4A785D-M PRO - 405 Official Bios - SUCCESS!! *Thanks ptblank*
M4A785M - 0503 Official Bios - SUCCESS!! - *Thanks Bkobe7*
785G/SB750
M4A785TD-V EVO - 410 Official Bios - SUCCESS!! - *Thanks Frefox1337*
790X/SB750
M4A79XTD EVO - 0605/0704 Official Bios - SUCCESS!! / http://www.overclock.net/amd-cpus/53...ml#post8199976 - *Thanks Mr Sprinkles and Lancer33*
790FX/SB750
M3A79-T Deluxe – 0030 Mod Bios - SUCCESS!!
M4A79 Deluxe – 1602 Official Bios – SUCCESS!!
M4A79T Deluxe – 0079 Mod Bios/1801 Official Bios – SUCCESS!!/TRI-CORE SUCCESS!! *Thanks T1Cybernetic*
Crosshair III Formula - 0702 / 1003 - FAILURE / SUCCESS!! *Thanks Gz1*
790GX/SB750
M3A78-T – 0023 Mod Bios – SUCCESS!!
M4A78-E – 1204 Official Bios – SUCCESS!!
M4A78-E SE – 0023 Mod Bios – SUCCESS!!
M4A78T-E – 1402 Official Bios – SUCCESS!! - SUCCESS #2!! *Thanks AMDRick*

Asrock
780G/SB710
A780GMH/128M - 1.50 Bios - SUCCESS!! *Thanks giveen*
790GX/SB750
AOD790GX/128M – 1.40 Bios – SUCCESS!!
A790GMH/128M - 1.20 Bios - SUCCESS!! *Thanks fortesquieu*
A790GXH/128M – 1.20 Bios - SUCCESS!!
A790GX/128M - ???

Biostar
For Biostar special bioses for core unlocking, visit this thread
For ALL Biostar bioses released + modded ones, visit here
785G/SB710
TA785G3 - ???
TA785GE 128m - 88GCO720CE Mod Bios - SUCCESS!!
790GX/SB750
TA790GXB3 - ???
TA790GXBE - ??? - SUCCESS!! *Thanks alg33k*
TA790GXE - Mod Bios available - ???
TA790GXE 128M - Mod Bios available - ???
TA790GX A3+ - 78DAA616 Mod bios – SUCCESS!!
TA790GXB A2 - Mod Bios available - ???
TA790GX 128M – 78DEA113 Official bios – SUCCESS!!
TA790GX3 A2+ - A78DA113 - SUCCESS!! *Thanks DesertRat*
TA790GX XE - Mod Bios available - ???
TA790GX A2+ - 78DBA113 Official bios - SUCCESS!!

DFI
790X/SB750
DK 790X-M2RS - ???
790FX/SB750
DK 790FXB-M3H5 – 04/02/2009 Bios – SUCCESS!!
DK 790FXB-M2RSH – 03/10/2009 Bios- SUCCESS!!
DK 790FXB-M2RS - 02/24/2009 Bios - SUCCESS!! *Thanks eXe.Lilith*
790GX/SB750
DK 790GX-M2RS - ???
JR 790GX-M2RS – 10/30/2008 Bios – SUCCESS!!

ECS
Unfortunately, ECS has decided not to support unlocking in line of motherboards. LINK

Gigabyte
nForce 720D
GA-M720-US3 - F4 Bios - SUCCESS!! *Thanks rnscotch*
760G/SB710
GA-MA78LM-S2 - F1 Bios - SUCCESS!! *Thanks Zaishen*
770X/SB710
GA-770TA-UD3 - F1 Bios - SUCCESS!! *Thanks cloud8521*
GA-MA770T-UD3P - F2c/F3 Bios - SUCCESS!!/SUCCESS!! *Thanks Miked270 and oxymorosis*
785G/SB710
GA-MA785GM-US2H - F5 bios SUCCESS!! *Thanks khoas07*
GA-MA785GMT-UD2H - F3/F5 Bios - SUCCESS!! / SUCCESS!! *Thanks KayCi and mR_sage*
785GX/SB750
GA-MA785G-UD3H - F1/F5b Bios - SUCCESS!! / SUCCESS!! *Thanks Nubster and Nburnes*
790X/SB750
GA-MA790X-DS4 - ????
GA-MA790X-UD3P - F4 Bios - SUCCESS!!
GA-MA790X-UD4 – F3 Bios – SUCCESS!! *Thanks kromar*
GA-MA790X-UD4P – F5/F7/F9 Bios – SUCCESS!! / SUCCESS!! / SUCCESS!! *Thanks Deuces*
GA-MA790XT-UD4P - F4G/F5/F6/F7 Bios - SUCCESS!! / SUCCESS!! /SUCCESS!! *Thanks Broodman, Dramamine, and derekb*
790FX/SB750
GA-MA790FX-UD5P - F4c Bios - SUCCESS!! *Thanks PKV*
GA-MA790FXT-UD5P – F3b/F5 Bios – SUCCESS!! / SUCCESS!! *Thanks jbranton*
790GX/SB750
GA-MA790GP-DS4H – F3h Bios – SUCCESS!!
GA-MA790GP-UD3H - F1 Bios - SUCCESS!!
GA-MA790GP-UD4H – F3h Bios – SUCCESS!!
GA-MA790GPT-UD3H - F2 Bios - SUCCESS!! *Thanks inimical*

MSI
For MSI special bioses for core unlocking, visit this thread.
770X/SB710
770-C35 - Special Bios – ???
770-C45 – 1.3 Offical Bios/1.3B2 Special Bios – SUCCESS!!/SUCCESS!! *Thanks Edgemeal*
785G/SB710
785GT-E63 - 28.0 08/13/2009 Bios - SUCCESS!! *Thanks rolanista*
785GTM-E45 - 8.0 09/07/2009 Bios - SUCCESS!! - *Thanks tacoman*
790X/SB710
790XT-G45 - ???
790FX/SB750
790FX-GD70 – 1.5B1/1.5B2/1.5B3 Bios – SUCCESS!! - (Solves previous 1.4 bios lockup problems, but 1.5B2 and 1.5B3 has HT link stuck at 8x and 10x multiplier respectively. See thread for details.)
790GX/SB750
790GX-G65 – 1.4B2 Special Bios - SUCCESS!! *Thanks mr.05'rsx*
DKA790GX - 1.8 Bios for Platinum version of mobo - SUCCESS!! *Thanks NeoAnderson*
DKA790GX Platinum – 1.9b2 Bios - SUCCESS!! *Thanks Rosaki*
KA790GX - FAILURE
KA790GX-M - FAILURE
Special note about KA790GX/KA790GX-M motherboards: Even though these two motherboards have a SB750, the traces to activate ACC are not soldered on the PCB. As a result, they WILL NOT unlock anything.

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 designation starting with X4. 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 12 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. For those on a budget, the Xigmatech s1283, OCZ Vendetta 2, and the Sunbeam Core Contact Freezer are the recommended choices. Those who have unlimited budgets will want a Prolimatech Megahalem, or more exotic cooling solutions such as water or TEC. Keep your cpu cool, and it will reward you back with high overclocks.

Conclusion
Good luck with Phenom II core unlocking. The take-home point however, is the following:
AMD Phenom II X2 and X3 processors have disabled cores which can be unlocked using the right motherboard and BIOS. Ultimately, however, those cores were disabled for a reason. Whether you are able to get those unlocked cores stable is where luck plays a part. Read this guide, pick the right cpu+motherboard combination, and good luck.

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.

Cavi

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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raxen

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.

Dopamin3

+rep
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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jimibgood

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.

bucdan

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

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raxen

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.

Bartmasta

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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Dopamin3

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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jimibgood

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.