*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抦 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抯 answer to Intel抯 Core2Duo and Core2Quad series. Unlike the Core2Quad, which is essentially two Core2Duo抯 bridged together, AMD抯 Phenom II is a chip with four individual cores.
Like all manufacturing processes, chip fabrication is no different. There are always parts which don抰 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抯 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 揹efective
Choosing the right processor
As previously mentioned, all of AMD抯 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抰 end up unlocking the 4th core by following this guide, you can抰 go wrong because you still would have gotten the best bang for your buck. These chips are proven overclockers.
1.AMD Phenom II X2 550BE
2. AMD Phenom II X3 720BE
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.
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.
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
Post time 29-1-2010 03:47 PM
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