AMD's $300 6-Core CPU: Too Good to Be True?

Alex Castle

AMD’s new Thuban hexa-core CPUs come out swinging with prices that belie their size

If we’ve learned anything from years of watching action movies: You never, ever count out the underdog. Such is the case with perennial underdog AMD.

Bloodied, beaten, and bruised by months and months of Intel chips that outpaced its parts, AMD isn’t giving up. Instead, it’s hitting back with its own hexa-core CPUs and doing everything just short of yelling yippie ki-yay!

And now for the shocker: These hexa-core CPUs are affordable. Hell, one of the parts is practically budget-priced. Intel’s high-flying hexa-core Core i7-980X is $1,000. Contrast that with AMD’s new 3.2GHz Phenom II X6 1090T at $295. Want more? The 2.8GHz Phenom II X6 1055T costs $200. Yes, $200 for a hexa-core processor. So yippie kay-yay mother frakker, ineed!

Want even more good news? AMD’s new chip will be backward compatible with the vast sea of AM3, and even older AM2+, motherboards out there. We’re quite glad to hear this, because at one point the company told us it planned to jettison DDR2 support, which would have cut off the AM2+ folks. Fortunately, the company changed its mind and both new chips include DDR3 and DDR2 support.


Just like with those Hollywood action movies, this story wouldn’t be complete without an element of suspense: Are AMD’s Phenom II X6 processors capable of whopping Intel’s similarly priced quad-cores, or even its $1,000 wonder, the Core i7-980X? To find out, you’re going to have to read on.

What’s the best budget chip available today for those interested in getting good performance on the cheap? We’ll walk you through the top five chips and tell you which one to buy.

CPU Specs
CPU
Phenom II X6 1090T Phenom II X6 1055T
Phenom II X4 965 Black Edition
Athlon II X4 630
Code-name
Thuban Thuban
Deneb Propus
Clock Speed
3.2GHz 2.8GHz
3.4GHz
2.8GHz
Turbo speed
3.6GHz 3.3GHz
N/A N/A
Cores
6
6
4 4
L2 Cache 3MB
3MB
2MB 2MB
L3 Cache 6MB 6MB 6MB N/A
Socket
AM3/AM2+ AM3/AM2+ AM3/AM2+ AM3/AM2+
AMD 125 watts 125 watts 125 watts 95 watts
Process 45nm
45nm 45nm 45nm
Die Size 346mm2 346mm2 258mm2 169mm2
Transistor Count
904 million* 904 million* 758 million 300 million
Price
$295 $200 $185 $100



*Transitor count not released. Figure is derived from AMD’s hexa-core Opteron part

Under the Hood of AMD’s Phenom II X6

In many ways, AMD’s new Phenom II X6 isn’t all that different from the Phenom II X4 processors. Both chips are built on a 45nm process, have the same 125-watt TDP rating, and feature the same microarchitecture. Of course, the Phenom II X6 is far larger than a Phenom II X4. A typical Phenom II X4 is 258mm2. The Phenom II X6 is about 40 percent larger at 364mm2. Oddly, AMD wouldn’t disclose the transistor count of the Phenom II X6, but we’d guess it’s the same or pretty close to the hexa-core Opteron 2435 at 904 million. On the surface, it would appear that AMD just took a Phenom II X4 and glued on two more cores. It’s not quite that simple, though. The L2 cache of the new chip remains at 512KB per core. The 6MB of L3 cache is also the same as with the older quad-core. That’s actually a reduction since the 6MB of L3 is shared among six execution cores instead of just four. Whether that plays into the performance of chip, isn’t yet clear. But AMD has made some other changes to boost performance.

Turbo Boost, Meet Turbo Core

AMD’s top-end Phenom II X6 1090T has a lower clock than the Phenom II X4 965 BE, but AMD makes up for that, and addresses the lack of applications and games optimized for six-cores, by introducing a new Turbo Core mode. Turbo Core overclocks three of the cores in the CPU when threading loads are light. The 1090T will Turbo Core from 3.2GHz to 3.6GHz, and the 1055T will Turbo Core from 2.8GHz to 3.3GHz. The mode is transparent to the OS and works without the need of drivers. It’s also not as discriminatory as Intel’s similar Turbo Boost, where apps that hit only one core will get more of a boost than apps that hit two or three. AMD said its tests show that the biggest benefits come from the three-core increase in games and apps that have not been optimized for four or more quads. Folks who want to mess with overclocking limits and ratios for Turbo Core can do so using AMD’s OverDrive utility.

Keeping Things Compatible

AMD’s strength has been its ability to make new chips work in older motherboards. In the three years that Socket AM2+ has been out, Intel has retired Socket 775 and introduced two new sockets that are incompatible with each other. That AMD can get its newest Phenom II X6 to work in older AM2+ boards (and probably even a few AM2 boards, too) is a testament to good planning. The only limiting factor for upgraders with the new Phenom X6 is likely a board’s thermals: The board must support 125-watt processors for the user to expect long-term reliability. BIOS updates will also be required, but AMD says that at launch, no fewer than 160 boards will have BIOS updates available to support the Phenom II X6.

Make Way for the 890FX Chipset

With the new chip, AMD is also introducing a new chipset series: the 8 series. The top chipset from AMD is the 890FX, which will replace the 790FX chipset. The 890FX has a big leg up over its Intel counterpart, the P55 chipset, in the number of PCI Express 2.0 lanes the chipset supports. One of the problems we’ve run into with the P55 lately is the lack of available PCI-E lanes to pass data from USB 3.0 and SATA 6 drives. With many P55 motherboards, installing two GPUs into the x16 PCI-E slots will handcuff the bandwidth of USB 3.0 and SATA 6 devices. Not all boards are affected, but most are. With 42 PCI-E 2.0 lanes available in the 890FX chipset, you can easily run multiple GPUs as well as your other devices without being constrained. Compare that to Intel’s P55 chipset which features 16 PCI-E 2.0 lanes in CPU and a pathetic eight PCI-E 1.0 speed lanes in the P55 chipset itself.

The new 890FX also features the SB850 south bridge with native SATA 6 support for six devices. The one key item missing from the SB850 is USB 3.0. Most board vendors are instead integrating NEC controllers to add the feature.

Inside the Phenom II X6

AMD’s new Thuban core is essentially the Istanbul core used in the Opteron 2435. Packing roughly 904 million transistors, the monolithic core has controllers for both DDR2 and DDR3 embedded in it. While the Opteron that it’s derived from has up to four Hyper Transport links for multiprocessor configurations, Thuban uses just one HT link to connect to the chipset.

So Is It Fast?

We put Phenom II X6 up against Intel’s best and brightest

As always, this is where the rubber meets the road, and to get a good feel for where Phenom II X6 1090T falls, we compared it to a spate of chips including the $282 2.8GHz Core i7-860, the $200 2.66GHz Core i7-750, the $195 3.4GHz Phenom II X4 965 Black Edition, and, of course, the $1,000 3.33GHz Core i7-980X.

We used identical GeForce GTX 280 cards in all of our test platforms, along with the same graphics drivers. For the Athlon testing, we used the new MSI 890-FXA GD70 motherboard. A Gigabyte GA-P55A-UD6 powered the LGA1156 parts, and an Asus P6X58D Premium handled the chore for the LGA1366 procs. All of the dual-channel boards used 4GB of DDR3/1333 RAM, while the triple-channel boards had 6GB of DDR3/1333. Windows 7 Professional and matched 150GB Western Digital Raptor 150 drives were used in all the platforms.

For benchmarks, we ran more than two dozen tests to find the strengths and weaknesses of AMD’s new chips. The results are interesting, to say the least.

First, the giant benchmark chart:

Click for larger benchmarks chart.

Video Encoding and Video Editing

In general, more cores mean better performance with multithreaded encoders and nonlinear editors, but there’s more to the story than cores. Phenom II X6 chips continues to feature a three-issue execution core vs. the Core i3/5/7 processors’ four-issue execution core. Against its natural competitor, the similarly priced 2.8GHz Core i7-860, the 1090T is at a big disadvantage, with encoding times in both Premiere Pro CS3 and Sony Vegas Pro 9 taking about 22 percent longer. HandBrake saw the 1090T do a little better, but AMD’s hexa-core was still about 14 percent slower than Intel’s quad. The closest the 1090T came to that chip was in our MainConcept Reference encoding challenge. The 1090T does a lot better against the Core i5-750, which doesn’t have the advantage of HyperThreading, but the 750 is also $100 cheaper.

3D Modeling

This is the where the Phenom X6 1090T shines the brightest. The 1090T aces both the Core i5-750 and Core i7-860 in Cinebench 10 and 11.5, and POV Ray 3.7. It even manages to outpace the $562 Core i7-870 in POV Ray and Cinebench 11.5.

Photo Editing

We saw hit-or-miss results here. Against the Core i7-860, the 1090T was faster in our Adobe Lightroom file-conversion test by a healthy 10 percent, but it got blitzed in our ProShow Producer slide show–creation test by 17 percent. Photoshop CS3 also saw the 1090T trailing by about 5.4 percent. In the heavily multithreaded Bibble 5.02, we saw both chips on equal terms, with the 1090T trailing just slightly by two percent. As you’d expect, the 1090T did much better against the Core i5-750 and much worse against the Core i7-870. We guess, as they say, you gotta punch your weight.

Memory Bandwidth

The 1090T actually has the highest memory bandwidth of the AMD CPUs and also aces the dismal memory bandwidth of the dual-core Core i3-530, but all three Clarkdale parts and the two LGA1366 CPUs leave the 1090T behind. One thing to keep in mind: Memory bandwidth is apparently not the end-all, be-all as the Core i7-980X has only mediocre bandwidth yet is still the faster processor here.

Gaming

The area where the 1090T was most disappointing was gaming. Against the Core i7-860, we saw the 1090T trail by double digits in Far Cry 2, World In Conflict, Resident Evil 5, and the Valve Particle Test. The best that the 1090T did was in Dirt 2, where it beat the Core i7-860 by 28 percent. However, we suspect that our Core i7-860 score is an error on our part as it doesn’t line up with the how the Core 5-750 and Core i7-870 performed. Also, keep in mind, that we run our tests at very low resolutions. At normal gaming resolutions of 1920x1200, the performance really shifts to GPU land, and you would find the margins closing up to the point where the CPU simply doesn’t matter that much to the average gamer.

The Verdict

We didn’t promise you an action-hero ending and you’re not getting one. In the performance story, it’s a mixed message. For the most part, Intel’s Hyper-Threaded quad-cores still have the edge. However, Phenom II X6 gets far closer than AMD has been of late. AMD fans may be a little disappointed that the X6 doesn’t spank the equivalent Intel parts, but there’s still a lot of good here. The Phenom II X6 has a great price, it’s probably compatible with the board you have in your machine now, and it gives you six cores. It may not be the happy ending some were looking for, but think of it like the end of Empire Strikes Back. Sure, Luke got his hand cut off, Vader is his pops, and Han got frozen in carbonite, but maybe, just maybe, there are better things coming on the horizon.

In-Depth Benchmarks:

1. Adobe Premiere Pro CS3


Our Premiere Pro CS3 benchmark is a bit older and certainly not as multi-threaded as our newer Sony Vegas Pro 9 test. For the test, we take 1080i footage capture from an HDV-based Sony HVR-Z2U, create a small movie, and output it to Blu-ray resolution in MPEG2. It’s not a bad workload for, say, four years ago. From our bench though, it’s clear the current K10 microarchitecture lags here even the Core i5-750 without Hyper-Threading is able to out perform the six-core Phenom II X6. The Core i3-530 does the worst, but we have to note, that it’s only a dual-core.

2. Sony Vegas Pro 9

Our Sony Vegas Pro 9 benchmark is a bit more modern. We’re using an EOS 5D Mark II to capture 1080p video at 30 fps (the 24 fps firmware was not available when we shot our video). A few simple transitions and a crap load of filters are added and the whole deal is outputted to Windows Media 11. We’ve seen Vegas able to hammer all six cores plus the six Hyper-Threaded cores in an Intel Gulftown so we had high hopes for the 3.2GHz Phenom II X6. The chip actually does well leaving the 3.4GHz Phenom II X4 and the budget 2.8GHz Athlon II X4 in the dust, but the Phenom X6 still just barely comes up behind the 2.66GHz Core i5-750. That leads us to wonder if the Intel’s wider chips (4 issue vs. the 3 issue of the AMD parts) is partially responsible for the performance gap or if the Intel’s SSE performance is simply superior.

Read on for 21 more flavor-packed benchmark charts!

3. Main Concept Reference 1.6

We use Main Concept Reference 1.6 to convert the 1080p MPEG2 video spit out from our Proshow Producer 4.0 into a much smaller H.264 format at 1080p resolution. Main Concept Reference is a good performance indicator of a chip because Main Concept’s primary business is selling CODECs that get used in hundreds of different products. We like to say that if it does well in Main Concept, it’ll probably do well everywhere.
The Phenom II X6 gives a good show by acing the Core i5-750. However, it’s still a bit slower than the Core i7-860 which is its naturally priced competitor. Still, it’s a good showing and after the trouncing in Vegas and Premiere CS3, the Phenom II X6 numbers here were far more encouraging.

4. Handbrake 0.9.4

For our Handbrake test, we use the open source app to convert DVD-resolution source files into an MPEG4 file formatted for use in an iPhone. The Phenom II X6 is sandwiched in between the Core i7-860 and the Core i5-750 again. It’s not a bad showing but the Core i7-860 continues to look like the better part for video editing and video transcoding.

5. Maxon Cinebench 10

Maxon’s Cinebench 10 has long been a popular benchmark for those looking to measure the 3D modeling performance of CPUs using a retail product. Performance here will tell you how much performance you would get if you were to use the company’s Cinema 4D product. After stumbling out the gates in our video tests, the Phenom II X6 roars back. It’s six real cores, easily stomp the Core i5-750, and runs right past the Core i7-860 too. The higher clocks of the 2.93GHz Core i7-870, however, still keep it ahead of the Phenom II X6. The Core i7-870, however, is a $562 chip.

6. Maxon Cinebench 11.5

Cinebench 10’s main weakness has been problems scaling with the number of cores. Since the introduction of the six-core Core i7-980X, Intel has recommended that we use Cinebench 11.5 which uses more modern code from Cinema 4D. We’re pretty sure AMD would agree. Here we see the Phenom II X6 squirt past all of the LGA1156 Lynnfield chips. This is the Phenom II X6’s best showing yet and it initially led us to wonder if Intel would cut the price of the Core i7-870 to match the Phenom II X6 1090T.

7. POV Ray 3.7

POV Ray is a free ray tracing that has been in the works since the 1980s. Again, the six real cores of the Phenom II X6 show their stuff by putting all three quad-core LGA1156 parts in their place. Oddly, the pricey Core i7-975 Extreme Edition actually performed slower than the Core i7-870 part. That stumble on the Core i7-975 CPU actually put the Phenom II X6 in second place behind the only other six-core part here: the Core i7-980X. The Phenom II X6 can’t touch the Core i7-980X, but at a third of its price, that’s a win for the Phenom II X6.

8. Bibble 5.02

Bibble 5 is built to scale up to, umm, more than 24 CPU cores. For our test, we time how long it takes to convert a couple of hundred RAW format still images shot with a Canon EOS 5D Mk II  into JPG images. We expected the Phenom II X6 to give a good showing and it does OK. It’s as fast as its natural competitor the Core i7-860 but we had higher hopes coming off the chips exceptional performance in 3D modeling. One other thing to note here: the dual-core (but Hyper-Threaded) Core i3-530 part actually pushes the quad-core Athlon II X4 out of its way. So, it’s not always about cores.

9. Adobe Photoshop CS3

Our Photoshop CS3 test is an older test and uses a RAW file shot with a EOS 1D Mk IIn and runs about every filter available on it. It’s modeled after the anti-Apple test of the old Power PC vs. x86 days. That’s when Apple would cherry pick filters to run on an image in Photoshop and declare victory to the world. We decided to run ‘em all and let God decide who was faster. The test isn’t purely a CPU test as the hard drive speed can play a pretty significant role. One shocker: We thought the Phenom II X6 would easily beat the Phenom II X4 because of its Turbo Core feature, but the two chips were basically even. We even checked to see if Turbo Core was working and it was.

10. Lightroom 2.6

Our Adobe Lightroom converts several hundred RAW photos taken with a Canon EOS 5D Mk II into Adobe’s DNG format. The Phenom II X6 actually does very well coming just behind the Core i7-870 part. The truth is that isn’t much of a CPU test, it’s more of a system, hard drive test but a good showing is a good showing.

11. ProShow Producer 4

We use ProShow Producer to create a JPEG slide show which is then output as an MPEG2 video file with an audio track. It’s multi-threaded and the Phenom II X6 is the fastest of the AMD parts but it comes in considerably behind the cheaper and lower-clocked Core i5-750 part. This may, again, be a symptom of the Phenom II’s general performance issues in video encoding.

12. Fritz Chess Benchmark

Fritz Chess benchmark tests how fast a CPU can calculate chess moves using a real-world, chess game engine. The Phenom II X6, is again, sandwiched between the Core i7-860 and the Core i7-870 parts. From our chart, you can see those extra cores are working as the Phenom II X6 blows away its quad-core brothers and the Core i5-750 which has no Hyper-Threading

13.PC Mark Vantage

PC Mark Vantage uses a lengthy suite of gaming, application, video and image editing tests to spit out a score approximating a PC’s general performance. It’s hard to say why the Phenom II X6’s performance is a bit underwhelming as there’s just so much in the benchmark. More cores do pay off for Intel though as the Core i7-980X is clearly on top here.

Next up: In-depth game benchmarks!

Gaming benchmarks

The Phenom II X6’s most disappointing performance came in our gaming tests. Although it pulls out OK numbers in 3DMark Vantage, the Intel parts are still ahead. In Far Cry 2, Dirt 2, and Resident Evil 5, the Intel quad-cores lead the way. Even in Valve’s Particle Test benchmark the Phenom is only able to squirt past the Core i5-750 chip. The Valve test dates back to the first quad-cores and was made to show off the power of multi-threading and physics. We’ve never seen this as something that would scale past four cores, but the hexa-cores seem to do well here.

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