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Meet Zosma: AMD's Quad-Core Phenom II X4 960T Gets Unlocked


I’ve talked to several motherboard manufacturers about their 890GX and 890FX boards. In the fight to differentiate, many rushed to add core-unlocking capabilities, making it possible to turn some triple-core CPUs into quad-core models, or even dual-cores into quad-cores, if you’re especially lucky.

Why was Tom’s Hardware not all over this capability until now? Well, back in April of last year, I did show you how to turn a Phenom II X3 720 into a Phenom II X4 920. But I haven’t put much energy into core unlocking since then due to the following:

  1. Core unlocking is not a science. We can’t tell you how to pick unlockable CPUs, and your chances of buying an unlockable processor are, as far as we’ve been able to tell, less than 50%.
  2. The difference between a mid-range and high-end AMD CPU is usually $100 or less. With that sort of modest price spread, we continually recommend simply buying the processor you really want, rather than banking on a core unlock that you might not achieve.

The fact of the matter is that AMD can lock up the cores on its CPUs for different reasons. There might actually be a manufacturing defect keeping a core from operating properly, in which case it makes sense to turn it off and sell the processor as a triple- or dual-core model rather than toss it. Or, the company can take a functional quad-core and disable logic in order to meet demand for less-expensive SKUs.

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Unlocked six-core 960T

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Locked quad-core 960T

At the end of the day, this is a less reliable mechanism for generating additional performance than traditional overclocking. It’s very hit and miss, and the gains only apply to threaded applications and workloads. I'll admit that finding a chip that unlocks feels a lot like buying a Lottery Scratcher and winning twenty bucks. Just be ready to lose more times than you win.

Six-Cores Cost More

But with the launch of its Thuban design, AMD’s flagship six-core model jumped an additional $100 over the previous quad-core king, leaping from $185 to $295. If you could turn a quad-core CPU into a hexa-core chip, there’d actually be some worthwhile savings to be had.

The problem, of course, is that AMD isn’t yet selling any quad-core processors based on Thuban. That all changes this quarter, though, when the company is expected to launch its Zosma design. Derived from Thuban, Zosma is a six-core processor with two cores disabled for one of the two reasons cited above.

We got our hands on one of the first Zosma-based CPUs, the Phenom II X4 960T, along with ASRock’s 890FX Deluxe3 motherboard, to preview what budget-conscious enthusiasts might expect to see once these CPUs become available.

Chris Angelini
Chris Angelini is an Editor Emeritus at Tom's Hardware US. He edits hardware reviews and covers high-profile CPU and GPU launches.