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:
- 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%.
- 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.
Unlocked six-core 960T
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.
Preliminary information on Zosma is still scarce, and since we didn’t get this processor from AMD, pricing data isn’t available. What we do know is that the Phenom II X4 960T runs at a stock 3 GHz clock rate and supports Turbo CORE technology. It also sports a 95W TDP, down from the 125W of AMD’s Phenom II X6 1090T flagship (naturally, that changes when you start turning on cores, overclocking, and upping voltages).
Now, you might have thought that core unlocking as a feature was dead, since AMD pulled ACC out of its SB850 southbridge. And for a while there, it was looking like the most visible motherboard vendors wouldn’t pursue core unlocking in the 8-series chipsets. Asus was the first to break rank, though, and others have since followed suit, enabling unlocking via a number of mechanisms.
On ASRock’s 890FX Deluxe3, you can either turn on core overclocking through a BIOS switch called ASRock UCC or by simply hitting the ‘x’ key during POST (subsequently pressing ‘d’ during POST turns off UCC). Naturally, our Phenom II X4 960T was chosen for its ability to unlock reliably. Temper your enthusiasm, though. Our sources at ASRock tell us that, out of 16 samples the company has tested, six are able to unlock to six cores. That's a 37% chance in a fairly small sample size.
Four cores, 3.9 GHz
Six cores, 3.6 GHz
Do Unlocked Cores Hurt Overclocking?
If we assume that at least a percentage of locked cores are marginal compared to the four cores AMD leaves enabled, then turning those two disabled cores on risks system stability, increases power consumption, and very likely hurts your chances to hit as aggressive of an overclock.
We tested this out a bit using our Phenom II X4 960T sample and found that hitting 3.9 GHz was not a problem for this 3 GHz chip using a 1.425V BIOS setting. Turning on the two locked cores forced us down to 3.6 GHz to avoid crashing as Windows loaded up, and the extra heat forced a voltage reduction to 1.4V.
The moral of the story is (and this should be no surprise) turning on disabled cores will likely cap your maximum overclock on conventional air cooling, even if those cores are determined to be “good.” Weighing the pluses and minuses of pursuing parallelism or frequency will likely be a matter of evaluating the software you’re running. An extra 900 MHz from a 3 GHz quad-core chip on air is impressive. Those are the numbers we’d expect from an Intel Core i5 or i7 CPU, so it’s good to see AMD’s improved 45 nm process yielding additional scalability.
In the interest of including plenty of comparison data, we ran the Phenom II X4 960T in a handful of tests from our benchmark suite and plugged the results into charts from our Phenom II X6 1090T review. Thus, the charts you see on the following pages will likely look familiar, with the addition of numbers for the stock Phenom II X4 960T and the unlocked X4 960T.
| Test Hardware | |
|---|---|
| Processors | AMD Phenom II X4 960T (Zosma) 3.0 GHz, Socket AM3, 4 GT/s HyperTransport, 6MB L3, Power-savings enabled |
| AMD Phenom II X6 1090T (Thuban) 3.2 GHz, Socket AM3, 4 GT/s HyperTransport, 6MB L3, Power-savings enabled | |
| Intel Core i7-980X (Gulftown) 3.33 GHz, LGA 1366, 12MB L3, Hyper-Threading enabled, Power-savings enabled | |
| Intel Core i7-975 Extreme (Bloomfield) 3.33 GHz, LGA 1366, 8MB L3, Hyper-Threading enabled, Power-savings enabled | |
| Intel Core i7-930 (Bloomfield) 2.8 GHz, LGA 1366, 8MB L3, Hyper-Threading enabled, Power-savings enabled | |
| Intel Core i7-920 (Bloomfield) 2.66 GHz, LGA 1366, 8MB L3, Hyper-Threading enabled, Power-savings enabled | |
| Intel Core i5-750 (Lynnfield) 2.66 GHz, LGA 1156, 8MB L3, Power-savings enabled | |
| AMD Phenom II X4 965 BE (Deneb) 3.4 GHz, Socket AM3, 4 GT/s HyperTransport, 6MB L3, Power-savings enabled | |
| Motherboards | ASRock 890FX Deluxe3 (Socket AM3) 890FX/SB850 |
| MSI 890FXA-GD70 (Socket AM3) 890FX/SB850, BIOS A7640AMS | |
| Gigabyte X58A-UD5 (LGA 1366) X58 Express, BIOS F4 | |
| Gigabyte P55A-UD7 (LGA 1156) P55 Express, BIOS F4 | |
| Asus M4A79T Deluxe (Socket AM3) 790FX/SB750, BIOS 2304 | |
| Memory | Corsair 6GB (3 x 2GB) DDR3-1600 7-7-7-20 @ DDR3-1333 |
| Corsair 4GB (2 x 2GB) DDR3-1600 7-7-7-20 @ DDR3-1333 | |
| Hard Drive | Intel SSDSA2M160G2GC 160GB SATA 3 Gb/s |
| Intel SSDSA2MH080G1GN 80GB SATA 3 Gb/s | |
| Graphics | Sapphire Radeon HD 5850 1GB |
| Power Supply | Cooler Master UCP 1100W |
| Heatsink | Intel DBX-B Thermal Solution |
| System Software And Drivers | |
| Operating System | Windows 7 Ultimate 64-bit |
| DirectX | DirectX 11 |
| Platform Driver | Intel INF Chipset Update Utility 9.1.1.1015 |
| Graphics Driver | Catalyst 10.2 |
Benchmarks and Settings | |
|---|---|
Audio Encoding | |
iTunes | Version: 9.0.2.25 (64-bit), Audio CD ("Terminator II" SE), 53 min., Default format AAC |
Video Encoding | |
MainConcept Reference 1.6.1 | MPEG2 to MPEG2 (H.264), MainConcept H.264/AVC Codec, 28 sec HDTV 1920x1080 (MPEG2), Audio: MPEG2 (44.1 KHz, 2 Channel, 16-Bit, 224 Kb/s), Mode: PAL (25 FPS), Profile: Tom’s Hardware Settings for Qct-Core |
| HandBrake 0.9.4 | Version 0.9.4, convert first .vob file from The Last Samurai to .mp4, High Profile |
Applications | |
Autodesk 3ds Max 2010 (64-bit) | Version: 2009 Service Pack 1, Rendering Dragon Image at 1920x1080 (HDTV) |
WinRAR 3.90 | Version 3.90 (64-bit), Benchmark: THG-Workload (334 MB) |
7-Zip | Version 4.65, Built-in Benchmark |
| Adobe Photoshop CS4 | Radial Blur, Shape Blur, Median, Polar Coordinates filters |

Because iTunes isn’t threaded, we wouldn’t expect it to show the six-core Phenom II X4 960T any advantage over the quad-core version. Indeed, it doesn’t. And the 960T’s relatively low base clock rate also relegates it to last place. With that said, this CPU is Turbo CORE-enabled. And while we don’t know whether the official top speed will be 3.3 or 3.4 GHz, we saw our sample hitting 3.4 GHz via a 17x multiplier during testing. Clearly, unless you're overclocking, the 960T is going to leave you wanting in single-threaded apps.

MainConcept is much more appreciative of additional processing resources. Here we see the last-place X4 960T being catapulted ahead of the Core i7-930 after being unlocked. In this case, the 3 GHz unlocked CPU falls just behind the 3.2 GHz Phenom II X6 1090T.

Similarly, HandBrake shows that jumping from four cores to six makes a huge difference in media transcoding applications. While AMD’s 1090T jumps ahead of Intel’s $1,000 Core i7-975 Extreme, the six-core 960T falls one step behind -975.

3ds Max is threaded, so jumping from four to six cores yields a fairly significant speed-up in rendering performance. The performance gain isn’t as pronounced here as it was in the transcoding tests, but it’s still enough to put the six-core Phenom II X4 960T in front of Intel’s Core i5-750.

We’ve made a concerted effort to transistion much of our 2010 test suite to threaded software, recognizing that single-core CPUs and single-task workloads are a thing of the past. These threaded Photoshop filters prove the value of a six-core CPU. And even though the Zosma design doesn’t jump to the top of our chart, just the difference between the stock four-core configuration and our unlocked processor should be enough to convince content creators to either consider outright buying a six-core chip or to consider core unlocking.

Although AMD’s processors bring up the back of the pack in WinRAR, the addition of two cores is enough to move our Phenom II X4 960T from last place to in front of the Deneb-based X4 965 Black Edition.

Our last productivity-oriented test shows our six-core sample again jumping up in front of AMD’s Phenom II X4 965, tying the Core i7-920 and 930 processors in our 7-Zip compression routine.
Our goal here is to provide a first look into the potential gains of unlocking AMD’s upcoming Phenom II X4 960T, but our early benchmarks are more telling than that.

In light of the fact that pricing data isn’t yet available for AMD’s upcoming creation, we’re left to a bit of guessing. Very consistently, the X4 960T falls behind the previous quad-core flagship, the X4 965 Black Edition. That part is currently priced at $185 on Newegg. The X4 955 comes in at $159. I’d expect AMD to debut its Zosma-based X4 960T somewhere in between.
At that price, and with a bit of overclocking, an unlocked 960T would be quite a value versus the Phenom II X6 1090T at $310. Just remember, if you plan to try your hand at unlocking, you’ll need a board that explicitly supports this feature, like ASRock’s 890FX Deluxe3. Because the SB850 southbridge doesn’t expose ACC functionality, it’s now up to the motherboard vendors to enable core unlocking.
As we’ve observed in the past, I can’t imagine that AMD likes the fact that power users are able to turn on disabled cores. But it can’t ignore the fact that core unlocking, unlocked multipliers, aggressive memory profiles that overclock northbridge frequencies, and low prices are what has helped earn the company accolades amongst enthusiasts, despite the fact that Intel sells faster CPUs.
Of course, while it’s entirely possible that you’ll be able to buy an unlockable 960T, it currently looks like there’s a better than 50% chance of not getting a successful core unlock. With that said, it’s hard to ignore the Phenom II X6 1055T priced at $205, which should consistently outrun Intel’s Core i5-750 in threaded workloads. If you aren't feeling adventurous enough to risk money on a quad-core processor that might actually be an undercover hexa-core champ, go the safe route and overclock AMD's Phenom II X6 1055T.
Update: I just got off the phone with AMD to discuss this part. As it turns out, the Phenom II X4 960T may never see the light of day. This actually happened a while back with a part called the Phenom II X3 740; AMD simply decided that the processor wasn't something that fit well in its product stack. And truth be told, the company has a point, especially in this case. There are already compelling quad-core CPUs in its lineup, so why launch an expensive six-core-cut-down-to-four-core chip to compete against those? "To recover at least some of its investment into the Thuban die with dysfunctional cores" would be one suggestion, but it remains to be seen if there are enough of these to warrant a new SKU.
It might come to pass that Phenom II X4 960T emerges as an OEM component. But as it stands right now, don't expect this one to become a retail part.



