Saturday February 11, 2012 8:15 AM AEST

Unlock a Phenom 2 X3's fourth core

By Justin Robinson
10:08 Feb 25, 2009 | 6 Comments
Tags: Phenom | 2 | X3 | X4
Unlock a Phenom 2 X3's fourth core

Simple BIOS trick unlocks the disabled core on Phenom II processors.

AMD have had a pretty good architecture going with their current Phenom II CPUs, based around a monolithic design that includes four cores on the one die.

Intel's Quad Cores in the Core 2 Quad have been essentially been two dual-core dies on the one package, giving a total of four cores split in the middle.

The advantage of the monolithic design is that you don't need to have the cores jump through the FSB or the HT bus to communicate, but a major disadvantage is that if a single part of the chip is faulty then there's a large possibility the entire chip will be unstable.

But if only one of the four cores is damaged, why not just disable it and let the other three functional cores keep going? And that's exactly what AMD did.

Users on the VR-Zone forums discovered that a certain batch of Phenom II X3 processors (0904) could be run in any 790GX based mobo and have their fourth core unlocked - just check the thread to see the thousand-point increase in 3DMark06.

The solution was pretty simple:

Go to BIOS, modify Advance Clock Calibration to Auto...now save the BIOS, restart and wait to see the magic...

Not all X3's will be entirely stable when the fourth core is reactivated, but if you've bought or are planning to buy and can activate one reliably - why wouldn't you?

Be sure to let us know your successes too - we'd be interested to hear if any other models of the X3 can do this too.

 

 
 
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6 Comments
smadge1
Feb 25, 2009 2:02 PM
Wasn't the idea of the X3 to sell quad core processors with 1 faulty core? Just locked off.
Cummings
Feb 25, 2009 4:36 PM
You read the article, right?

"But if only one of the four cores is damaged, why not just disable it and let the other three functional cores keep going? And that's exactly what AMD did."

"Not all X3's will be entirely stable when the fourth core is reactivated, but if you've bought or are planning to buy and can activate one reliably - why wouldn't you?"
nesquick
Feb 25, 2009 5:21 PM
stupid AMD for not laser etching the bad core off.
fliptopia
Feb 26, 2009 8:06 AM
stupid? why stupid? You sell a cpu that in all likelyhood will be not much good with 4 cores as a three core chip, you sell dozens to enthusiasts who think they can get 4 cores for cheap after this discovery. Great marketing.
xtort
Feb 26, 2009 8:07 AM
Laser etching = more handling which = higher production costs which means we pay more. not so stupid
Sparky
Feb 26, 2009 9:52 PM
This is fantastic. AMD knows they need to get back in the enthusiast game - it's what pushed the original athlon and A64 ahead.

They are giving this to us. In time yields will be high and triples will all do this for us. I hope.

At least thats what I would do if in AMD marketing.
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