Ok, let’s face the facts. Phenom X3 and new Athlon X2 are nothing else but a Deneb core (Phenom X4) that either failed the quad-core validation – or lower-core parts were needed more than quad-cores. Production cost was the same in any case.
Intel was the first manufacturer to introduce this “element” into the mix, way back in late 1990s. First “expensive turned cheap” processor was a certain Celeron processor that shared the same die as more expensive Pentium III processors. But the caveat was that specific boards recognized that CPU as Celeron with whole amount of cache, and those beasts were more overclockable than PIII processors (due to difference in FSB – 100 MHz vs. 133 MHz). And as the song goes, “here we go again”. Korean enthusiast web-site Playwares found out that Advanced Clock Calibration feature on SB700/750-equipped motherboards could be the way how AMD is creating X3 and X2 CPUs, and started to play with them on Biostar’s 790GX motherboard.
How to make a "Phenom X4 10": One X3 10, Overclocking-friendly motherboard and Page Down key on a keyboard.
As you can see in picture above, really interesting thing happened. One press on Page Down key in BIOS turned X3 into an X4, and by the stroke of luck, this X3 didn’t had a broken down core, but was one of those CPUs that was “cored-down”. Sadly, I don’t have Athlon X2 or Phenom X3 CPU here (have ASUS and GigaByte 790GX+SB750 motherboards) to test myself, but those motherboards have the same BIOS feature as tested Biostar one.
Unless this story is a hoax, all we can say is – it looks like AMD is not certain how many heads its Dragon platfrom has. It morphs 
I red about this last nite on toms hardwair forrom it was posted by a Korean. I must admit that i did not believe it and he was getting flamed left write and senter. But you have got to admit that’s a nice tuch if you have just gon out and bort a tri cor and you get it home and it’s a quad. I would be so chuffed!
By: tapper on February 23, 2009
at 14:06
Yep… well, I am intrigued… I would like to see somebody doing that on Phenom X3 720 Black Edition, since it’s unlocked
In any case, consumer wins
By: theovalich on February 23, 2009
at 14:10
There is a thread about a guy who was able to do this with his X2 7750 on AnandTech. His CPU actually read as Engineering Sample, even though he purchased it on NewEgg. I wonder if all AMD chips can do this, or just select ones that used to be engineering samples.
By: MasterYoda34 on February 24, 2009
at 00:38
Well, according to sources, this was done on a retail CPU. Sadly, I cannot check
By: Theo Valich on February 24, 2009
at 00:55
I have a TA790GX A2+ and with last years BIOS and the latest official it works and I’m here to tell you that I couldn’t believe it until I loaded Windows Task Manager and saw 4 cores running. I had to stare at it for an hour or so but it finally sank in that I now have an X4 CPU. Thankyou, thankyou, thankyou!
By: Stan Zaske on February 24, 2009
at 01:24
Best thing AMD could do now is to ignore it… and sell X3s as hot cakes. Without shortages they will sell all they can produce in months, even without “Black” mark on boxes. And finally makes some money on CPUs as well.
By: longo213 on February 24, 2009
at 13:03
We’ll see.. all I know is that I would really like to have X3 in a notebook 2.0 GHz clock with 4GB with DDR3-1333 and 790GX.
I am spoiled on the desktop side
By: theovalich on February 24, 2009
at 13:31