How to unlock 4 cores on AMD Phenom II 550 BE/710/720 BE

[NinjaRicer]

Hello there! You've come here because you'd probably like to unlock the fourth cores on the Phenom II X2 550 BE, X3 710, or the X3 720 BE. The X2 is a dual-core, and both of the X3's are triple cores. But wait, you must be saying to yourself "those aren't quad-cores!". In truth, they are. AMD disabled their cores for one of two very important reasons.

1. AMD disabled the cores knowing that they are faulty.

or

2. AMD disabled the cores because they wanted to push out more of that processor.

If AMD disabled the cores because they were faulty, that means those cores are bad. You don't want to enable those cores. If AMD just disabled the cores to push out more processors, then you can unlock them and be 100% stable with them! Now, for the actual unlocking.

Pre-Requisites

What you're going to do is go into something called the BIOS. It's what you see every time you turn on your computer. Now before that, there are some pre-requisites.

1. An AMD Phenom II X2 550 BE, Phenom II X3 710, or Phenom II X3 720 BE. BE stands for Black Edition.

2. An AMD motherboard that has an SB750 or SB710 south bridge chipset, or you may have a nVidia chipset as well. The motherboard must support unlocking cores as well. You can find a list below.

The board I am going to be demonstrating with is the Biostar TA790GX 128M, BIOS revision78DEA113. If you are going to be using this board, you need to have this BIOS revision, otherwise the process will not go smoothly. This also applies to certain motherboards as well, although with different BIOSes.

Warning

Now, some of you would guess there would be something to worry about when unlocking these cores. When unlocking these cores, your computer may not boot. This is nothing to worry about, it's just that your CPU may have faulty locked cores or you may have the wrong BIOS. Just reset your CMOS after this. Do not attempt this without looking at the motherboard list and BIOSes below.

Unlocking the Cores

First, boot into the BIOS. I pressed the 'Delete' key multiple times to get into the BIOS on my motherboard. This is what it looked like when I booted into the BIOS.



Next, I went over one menu to the right and into the 'Advanced' menu.



Then, I went into the 'CPU Configuration' menu. Notice how the processor is currently states the CPU is the Phenom II X3 710. Ignore the frequency clocks. Yours may be different.



Now, for the unlocking. I then went to the 'Advanced Clock Calibration' option and set it to 'AUTO'. Setting that to AUTO is a must. For some of you with nVidia chipsets, it may be called NCC.





Then, with the ACC setting at AUTO, I hit F10 and pressed enter to save the configuration. Wait for your computer to reboot after this point.



Now, in the same CPU Configuration menu, instead of seeing the same Phenom II X3 710 processor, we now see the Phenom II X4 10. That means we have just unlocked the fourth core!

Now, some of you would guess there would be something to worry about when unlocking these cores. When unlocking these cores, your computer may not boot. This is nothing to worry about, it's just that your CPU may have faulty locked cores or you may have the wrong BIOS. Just reset your CMOS after this.

Now, although I may be successful in unlocking my processor, some of you won't. That's because some of the processors actually had bad cores. If in the case your computer will not go back into Windows or the BIOS after following the steps above, you will need to reset your CMOS.

[NinjaRicer]

All information in this post is courtesy of raxen and the community at overclock.net! Visit them sometime. Currently, due to the character limit in posts, the updated motherboard list is here. http://www.overclock.net/amd-cpus/535501-amd-phenom-ii-core-unlocking-guide.html

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.

[NinjaRicer]

Asus *See Special Note Above*
GeForce 8300
M4N78 Pro - 1004 Official Bios - SUCCESS!! - *Thanks Henderson*
785G/SB710
M4A785D-M PRO - 405 Official Bios - SUCCESS!! Pending Screenshot
M4A785M - 0503 Official Bios - SUCCESS!! - *Thanks Bkobe7*
785G/SB750
M4A785TD-V EVO - 410 Official Bios - SUCCESS!! - *Thanks Frefox1337*
790X/SB750
M4A79XTD EVO - 0605 Official Bios - SUCCESS!! - *Thanks Mr Sprinkles*
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 - ???
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+ - 78DEA113 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*
770X/SB710
GA-MA770T-UD3P - F2c/F3 Bios - SUCCESS!!/SUCCESS!! *Thanks Miked270 and oxymorosis*
785GX/SB710
GA-M4A785GM-US2H - F5 bios SUCCESS!! *Thanks khoas07*
785GX/SB750
GA-MA785G-UD3H - F1 Bios - SUCCESS!! *Thanks Nubster*
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/F7 Bios - SUCCESS!! / SUCCESS!! *Thanks Broodman 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 - ???
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*
785GX/SB750
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.

[safeguy]

Thanks for the info...it looks interesting (and complicated...I didn't read everything yet)

Anyway this info isn't of use to me as I'm not using AMD....it's not widely used here in Singapore...INTEL is the king here for ready-made PCs...

P.S. If only someone here knows how to unlock 4 cores in Intel Core2Duo....

[NinjaRicer]

It's not difficult at all. If your processor and motherboard support unlocking, it's just as easy as changing one setting. If the BIOS is unable to unlock and there is another BIOS that can unlock, just flash your BIOS and change that setting.

[Kees]

The question is: did you get it stable on four cores? And did not it affect your cache?

[NinjaRicer]

The question is: did you get it stable on four cores? And did not it affect your cache?

My fourth core was stable and my cache stayed the same. Hell, I overclocked all four cores to 3.6 GHz completely stable.

[Chimera112]

Is it also working with a biostar GF8200C M2+ ?, because there is no acc in the Bios, and i cant find any Bios Mods for it

[hellnoire]

Is it also working with a biostar GF8200C M2+ ?, because there is no acc in the Bios, and i cant find any Bios Mods for it

If you can't see it, it would be logical that it wouldn't.

[Kees]

Biostar removed ACC from the BIOS features at the request of AMD (with whom they have good relations). You have to find a modded BIOS, something I do not recommend to the unadvanced user.