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AMD Phenom II X6 1090T And 890FX Platform Review: Hello, Leo
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1. AMD Can Do Six Cores, Too

At $1,000, it’s simply not possible to use the word value when talking about Intel’s Core i7-980X. Yes, it’s nice that the company is serving up an extra two cores at the same premium price point. And yes, we’re glad to see Intel extending the life of its LGA 1366 interface. But currently, your options for six-core CPUs from Intel include the Core i7-980X and Xeon 5600-series chips. Surprise—all of the hexa-core models are priced at a grand or more. Those prices pretty much only make sense for the folks running heavily-threaded apps in a work environment, who stand to save valuable time/money on encode projects.

AMD’s Opteron 2400-series processors also sport six cores, and they’re significantly less expensive (as low as $455 for the 2.2 GHz 2427). The compromise, of course, is that they’re not as fast. Here, you’re paying for the ability to enable a dual-socket machine equipped with twelve total cores. As with the Intel hexa-cores, these CPUs are totally overkill on the desktop.

Meet The Phenom II X6

Enter the Phenom II X6—what I’d consider to be the first viable six-core option for desktop power users.

The Core i7-980X demonstrated the benefits of increased processor parallelization versus Intel’s previous flagship, the Core i7-975. With both chips running at 3.33 GHz, it is easy to see where an extra two cores buys you better performance.

AMD’s new flagship Phenom II X6 is going to show us whether spending extra money on two extra cores is a smart move. After all, the Phenom II X4 965 Black Edition bears a $185 MSRP, while the Phenom II X6 1090T will go for $295. Does a 50% higher core count translate into a greater than 50% price bump?

I'll be honest. My immediate reaction would be that, no, simply adding two cores (and the corresponding L1/L2 caches that go with them) does not map over to a correspondingly higher price tag. But AMD is trying to sweeten the pot by introducing Turbo CORE technology, which we’ve already previewed. Briefly, Turbo CORE attempts to capitalize on the TDP headroom freed up when three or more cores are idle by dynamically overclocking the remaining three cores. On the Phenom II X6 1090T, Turbo CORE takes a 3.2 GHz CPU and boosts a trio of cores up to 3.6 GHz.

As a result, almost any way you cut it, a six-core Phenom II X6 should be faster than the Phenom II X4. The only exception would be when taxing exactly four threads causes the processor to drop to 3.2 GHz, keeping it from benefiting from the fifth and sixth cores, while operating at a lower clock rate than the 3.4 GHz Phenom II X4 965.

Say Hello To 890FX

That’s not all, either. AMD is also launching a revised version of its discrete-only desktop platform. The 890FX might sound like a spanking-new northbridge, but it’s really quite similar to the 790FX preceding it. You’ll find that the biggest difference is the SB850 southbridge accompanying the updated platform. We’ll dig deeper into that piece of logic shortly. For now, consider it part two of a new three-part platform AMD is calling Leo, successor to the Dragon platform. The third component is a Radeon HD 5800-series graphics card.

First, let’s talk about what it means to add two cores to the Phenom II family.

2. Phenom II X6: A Family Of Two

AMD is launching two Phenom II X6 processors: the 1090T and 1055T.

Both models are architecturally identical. That is to say they’re monolithic hexa-core designs with 128KB L1 cache per core (64KB instruction and 64KB data), 512KB of L2 cache per core, and a shared 6MB L3 cache.

This is, of course, a different approach than Intel’s. With its six-core Gulftown design, Intel increased the size of its shared L3 in order to maintain what its architects considered an optimal ratio between cores and cache. Because AMD isn’t also shifting to a smaller manufacturing process, it really can’t follow suit and keep the Phenom II economically viable at the same time. But as we’ll see in the benchmarks, simply increasing core count is enough to give the X6 a significant boost in threaded apps.

As I mentioned in my Phenom II X6 preview, AMD is sticking with its 45 nm process here. As a result, die size increases from 258 square millimeters to 346. And while AMD is hesitant to divulge official transistor counts, it admits that its Thuban design is closely related to existing hexa-core Istanbul-based Opteron CPUs. From that, we can safely assume the count lands around 904 million, up from approximately 758 million. That’s not as large an increase as Intel’s six-core design because Gulftown’s L3 is transistor-heavy. So, you can argue that AMD is getting the best return in performance for the added complexity. But while Intel was able to fit its 6-core/12MB L3 design into a smaller piece of silicon than the quad-core model that came before, AMD’s 346 mm² die represents a fairly large increase.

Though AMD won’t comment directly, we know through a handful of motherboard vendors that there will be Thuban-based quad-core CPUs following in the wake of the 1090T and 1055T. They’ll likely be armed with Turbo CORE as well, and apparently it’ll be possible for certain lucky buyers to unlock the two disabled cores. I don’t get excited about core unlocking for two reasons, though. First, it’s chance-based—you can’t tell if the processor you buy had cores turned off due to defect or simply to meet demand. Second, AMD’s price structure is so tightly packed that it makes the most sense to buy the CPU you want/need right off the bat, rather than roll the (wait for it)…dice.


Clock Frequency
Price
HT Speed
Lith. Node
Total L2 Cache
Shared L3 Cache
TDP
Voltage
Max. Temp.
Phenom II X6 1090T
3.2 GHz (3.6 GHz with Turbo)
$295
4 GT/s
45 nm SOI
3MB
6MB
125W
1.125-1.4V
62 C
Phenom II X6 1055T
2.8 GHz (3.3 GHz with Turbo)
$199
4 GT/s
45 nm SOI
3MB
6MB
125W
1.125-1.4V
62 C
Phenom II X4 965 Black Edition
3.4 GHz
$185
4 GT/s
45 nm SOI
2MB
6MB
125W (w/ rev. C3)
.825-1.4V
62 C


New Tech, New Names

In a world where every piece of technology-turned-marketing needs to be rolled into the name somehow, AMD follows in Intel’s footsteps by tacking another letter onto its product naming scheme.

Intel has the Core i7-980X, which, dissected, means absolutely nothing informative.

AMD now has its Phenom II X6 1090T and 1055T. At least the II is indicative of a second-generation Phenom family. The X6, of course, tells us that these processors are hexa-core—that’s fairly easy for most folks to figure out. The 1090 and 1055 are arbitrary performance indicators, and the T tells you these CPUs are Turbo CORE-enabled.

The 1090T runs at 3.2 GHz by default (down from the Phenom II X4 965’s 3.4 GHz). When Turbo CORE is active, it can hit speeds of up to 3.6 GHz, though as our experimentation on the next page shows, this isn’t something  seen on a regular basis. It sports a 2 GHz (4 GT/s) HyperTransport interconnect and is rated for a 125W TDP.

The 1055T operates at 2.8 GHz by default and runs at up to 3.2 GHz in Turbo CORE mode. It also boasts a 125W TDP, along with the same HyperTransport connection able to move up to 16 GB/s bidirectionally.

Both CPUs sport the same DDR2/DDR3-capable memory controller rated for DDR2-1066 and DDR3-1333 (officially). Performance-oriented memory modules listed in AMD's online database can be pushed at up to DDR3-1600, though, and simultaneously force lower latencies and overclocked northbridge freq./voltage settings.

3. Making Sense Of Turbo CORE

Turbo CORE is, without question, the one feature that took me the longest to dig into for this piece. First described by AMD as a deterministic capability, I took that to mean Turbo could tell when load was being applied to three or fewer cores, at which point it’d spin down three idle cores (dropping voltage and frequency) and overclock the other three, incrementing multipliers and voltage settings.

In my preview, I said:

“As far as we’ve been able to determine, Turbo CORE isn’t as granular as Turbo Boost. It operates based on operating system P-states, so when three or more cores are at low utilization levels and the active cores are in P0 (for more on P-states, check this out), the CPU capitalizes on TDP budget to increase performance by a flat 400 or 500 MHz.”

This isn’t the case, though. In practice, Turbo CORE really just works like Cool’n’Quiet in reverse. The processor can take a default 16x multiplier (on the 1090T) and increase it to 16.5x, 17x, 17.5x, or 18x, depending on activity. At the same time, you might not even see the other cores slow down at all.

Perhaps the best illustration I can give you is a couple of quick videos. In the first video, I’m running our iTunes benchmark, converting a WAV into an AAC file. This is a single-threaded workload, so we’d expect Turbo CORE to be doing its thing. You see the thread jumping from one core to the next in AMD’s OverDrive utility. At no point do we see any of the idle cores drop below 3.2 GHz. However, the active cores do hit 3.3 and 3.4 GHz.

Phenom II X6 1090T in iTunes


Now, I fire up a threaded workload like MainConcept, we see something different. For the most part, all of the cores operate, fully-loaded, at 3.2 GHz. Strangely, we actually do see certain cores peaking at 3.6 GHz with increased 1.475V spikes.

Phenom II X6 1090T in MainConcept


With none of our test workloads demonstrating three cores throttling down in response to higher clocks and voltages from the other three, I was worried that power might be suffering accordingly. If you remember back to my coverage of Core i7-920XM, I was concerned that Turbo Boost would keep the CPU at a higher frequency more of the time, and consequently burn through battery life faster. As it turned out, I was right, and an affinity for getting more done faster meant that Clarksfield was harder on energy use.

Anticipating something similar, I logged back-to-back PCMark Vantage runs on the Phenom II X6 1090T and X4 965 Black Edition:

These two actually map very closely. You’ll notice that the hexa-core chip does tend to peak at higher power numbers. Also, the lower red lines suggest that the quad-core contender drops to a lower idle power (also quite logical). But when you average out total consumption, the Phenom II X6-based system sits at 141W, while the X4-based machine uses 135W. That’s not bad.

At the end of the day, think of Turbo CORE as compensation for losing clock rate in the move to six cores. Just because the technology can hit 3.6 GHz on the Phenom II X6 1090T doesn’t mean you’ll get the equivalent of 3.6 GHz in single-threaded applications. Fortunately, at the same time, you’re also not paying a huge power price for the small bump in performance.

Turbo CORE on a single-threaded workload.Turbo CORE on a single-threaded workload.Turbo CORE on a multi-threaded workload.Turbo CORE on a multi-threaded workload.

Of course, there’s a caveat. As was the case at first with Intel’s Turbo Boost technology, it’s entirely possible that AMD’s monitoring tools aren’t capturing the true nature of what’s going on here. The refresh in OverDrive is quite slow, and processor states can change many times per second. AMD has assured me that the behavior I’m seeing sounds right, but there’s always that chance…

4. 8-Series Chipsets, Revealed

Yes, Phenom II X6 is a drop-in upgrade for existing Socket AM2+/AM3 motherboards. But that’s not stopping the company from launching a handful of chipsets alongside its six-core CPUs. The 8-series chipsets logically replace older 7-series parts, even if they’re fundamentally similar.

890FX

Starting from the top of the stack, the 890FX succeeds the 790FX as AMD’s discrete graphics-only flagship. The northbridge component sports 42 total PCI Express 2.0 lanes, 32 of which can be used for graphics (2 x 16 lanes or 4 x 8 lanes), four of which are ganged into a 4-lane link, and six of which attach to x1 devices like USB 3.0 and gigabit Ethernet controllers.

890FX also supports IOMMU (input/output memory management unit), which, in a virtualized environment, allows virtual machines direct access to hardware components by remapping I/O DMA transfers and device-generated interrupts. There are a couple of good examples where this might be particularly useful. In a workstation environment, Nvidia’s SLI Multi-OS technology lets you assign a dedicated GPU in a multi-card setup to one particular virtual machine using an app like Parallels’ Workstation 4.0 Extreme. Or, you could assign a specific Ethernet controller to one performance-sensitive VM, cutting back on the performance penalty that you’d suffer otherwise. Intel’s version of this technology is called VT-d, and has been around for a while now.

Like 790FX, 890FX is manufactured on TSMC’s 65 nm node and fit into a 29x29 mm package. Aside from its slightly-expanded suite of PCI Express connectivity, the northbridge’s only real notable change is a doubling of the bandwidth between itself and the SB850 southbridge, from 2 GB/s to 4 GB/s.


890FX
890GX
870
880G
Socket Support
AM2+/AM3
Interconnect
HyperTransport 3.0
PCI Express
2.0 / 42 lanes
2.0 / 22 lanes
2.0 / 22 lanes
2.0 / 22 lanes
CrossFireX Support
Yes
Yes
-
-
Virtualization
IOMMU 1.2
-
-
-
NB/SB Interface
x4 A-Link III
Integrated Graphics
-
Radeon HD 4290
-
Radeon HD 4250
DirectX
-
10.1
-
10.1
Playback Acceleration
-
UVD2
-
UVD2
Max. TDP
19.6W
25W
12.5W
18W
Process Technology
65 nm
55 nm
65 nm
55 nm
Package Size
29 x 29 mm
21 x 21 mm
21 x 21 mm21 x 21 mm
Southbridge

SB850
SB 710
USB Ports
14 USB 2.0 + 2 USB 1.1
12 USB 2.0 + 2 USB 1.1
SATA
6 x SATA 6Gb/s
6 x SATA 3Gb/s
FIS-Based Switching
Yes
-
Integrated Gigabit Ethernet
Yes
-
Clock Generator
Yes
-
PCI
2.3
2.3
Process Technology
65 nm
130 nm
Package Size
23 x 23 mm
21 x 21 mm


890GX

Launched last month, the 890GX is less enthusiast and more mainstream. It’s limited to 22 lanes of PCI Express 2.0 connectivity and includes an integrated Radeon HD 4290 graphics processor. Support for DirectX 10.1, hardware acceleration for video playback, and Stream technology support don’t change the fact that integrated graphics is best reserved for folks who don’t do much in 3D-oriented applications.

890GX does support CrossFireX, though. It thus becomes possible to buy a relatively inexpensive motherboard based on 890GX and upgrade it over time to sport a couple of discrete graphics cards that split 16 lanes of PCIe into two x8 links.

870

Likewise, the AMD 870 chipset boasts 22 PCI Express lanes as well. But because the value-oriented part doesn’t support CrossFireX, its single 16-lane graphics link is reserved for single-card configurations (and not divisible into a pair of x8 links). You won’t find an integrated GPU in this northbridge—it’s decidedly a discrete graphics-only value part.

As with all of the other 8-series chipsets, AMD’s 870 employs the same 4 GB/s A-Link III interface with whichever southbridge motherboard vendors choose to pair it up with.

880G

The entry-level integrated graphics chipset is still fairly well-equipped. 880G boasts 22 PCI Express 2.0 lanes, divisible into one x16 link and six x1 links. Its onboard GPU is called Radeon HD 4250, indicating its relative performance versus the 890GX’s Radeon HD 4290. Nevertheless, it still comes with video playback acceleration, Stream technology and post processing capabilities.

The SB850 Southbridge

While we’re not feeling the bandwidth bottleneck between northbridge and southbridge today, AMD’s integration of a SATA 6Gb/s controller onto its SB850 makes a data crunch much more plausible. Each 6 Gb/s port is theoretically capable of 600 MB/s. Times six ports, you’re looking at 3.6 GB/s. Factor in gigabit Ethernet and a pair of PCI Express 2.0 lanes (yes, the SB850 sports PCIe connectivity for the first time), and you’re in excess of the link’s throughput.

That’s not to say we’re in danger of getting anywhere close just yet. Storage devices are only just taxing the limits of 3 Gb/s SATA links, and it’s rare to see a gigabit Ethernet connection saturated as a pair of x1 PCI Express slots max out their potential bidirectional bandwidth. At the same time, it’s good to see AMD proactively prevent bottlenecks, especially knowing that motherboard manufacturers will be attaching USB 3.0 controllers and secondary network adapters to the southbridge.

As with southrbridge components prior, SB850 supports HD audio and its own PCI bus. SB850 also features up to 14 USB 2.0 ports.

5. Test Setup And Benchmarks
Test Hardware
Processors
AMD Phenom II X6 1090T (Thuban) 3.2 GHz, Socket AM3, 4 GT/s HyperTransport, 6 MB L3, Power-savings enabled

Intel Core i7-980X (Gulftown) 3.33 GHz, LGA 1366, 12 MB L3, Hyper-Threading enabled, Power-savings enabled

Intel Core i7-975 Extreme (Bloomfield) 3.33 GHz, LGA 1366, 8 MB L3, Hyper-Threading enabled, Power-savings enabled

Intel Core i7-930 (Bloomfield) 2.8 GHz, LGA 1366, 8 MB L3, Hyper-Threading enabled, Power-savings enabled

Intel Core i7-920 (Bloomfield) 2.66 GHz, LGA 1366, 8 MB L3, Hyper-Threading enabled, Power-savings enabled

Intel Core i5-750 (Lynnfield) 2.66 GHz, LGA 1156, 8 MB L3, Power-savings enabled

AMD Phenom II X4 965 BE (Deneb) 3.4 GHz, Socket AM3, 4 GT/s HyperTransport, 6 MB L3, Power-savings enabled
Motherboards
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 6 GB (3 x 2 GB) DDR3-1600 7-7-7-20 @ DDR3-1333

Corsair 4 GB (2 x 2 GB) DDR3-1600 7-7-7-20 @ DDR3-1333
Hard Drive
Intel SSDSA2M160G2GC 160 GB SATA 3 Gb/s

Intel SSDSA2MH080G1GN 80 GB SATA 3 Gb/s
Graphics
Sapphire Radeon HD 5850 1 GB
Power Supply
Cooler Master UCP 1100 W
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 DriverCatalyst 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

TMPGEnc 4.7

Version: 4.7.3.292, Import File: "Terminator II" SE DVD (5 Minutes), Resolution: 720x576 (PAL) 16:9

DivX 6.8.5

Encoding mode: Insane Quality, Enhanced Multi-Threading, Enabled using SSE4, Quarter-pixel search

Xvid 1.2.2

Display encoding status=off

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
AVG Anti-Virus 9
Virus scan of 334MB of compressed files

Synthetic Benchmarks and Settings

3DMark Vantage

Version: 1.02, GPU and CPU scores

PCMark Vantage

Version: 1.00, System, Memories, TV and Movies, and Productivity benchmarks, Windows Media Player 10.00.00.3646

SiSoftware Sandra 2010

CPU Test=CPU Arithmetic/Multimedia, Memory Test=Bandwidth Benchmark, Cryptography

Games
Crysis
High Quality Settings, No AA / No AF, 4xAA / No AF, vsync off, 1280x1024 / 1680x1050 / 1900x1200, DirectX 10, Patch 1.2.1, 64-bit executable
Left 4 Dead 2
High Quality Settings, No AA / No AF, 8xAA / 16xAF, vsync off, 1680x1050 / 1920x1200 / 2560x1600, Tomshardware Demo, Steam Version
Call of Duty: Modern Warfare 2
Ultra High Settings, No AA / No AF, 4xAA / No AF, 1680x1050 / 1920x1200 / 2560x1600, The Gulag, 60 second sequence, Fraps
DiRT 2
Ultra High Settings, No AA / No AF, 4xAA / No AF, 1680x1050 / 1920x1200 / 2560x1600, In-Game Benchmark, Steam Version
6. Benchmark Results: Synthetics

Vantage demonstrates that the Phenom II X6 1090T is faster than its predecessor in every one of the title’s synthetic disciplines, though not nearly to the extent that Intel’s Core i7-980X outperforms the Core i7-975. Yeah, I know. We’re talking about one $1,000 processor against another. But remember that AMD is asking $100 more for the X6 flagship versus the X4.

Clearly optimized for threading, the CPU benchmark is the only one that really matters much here, and it’s saying the six-core Phenom II outpaces the quad-core model. That doesn’t prevent Intel’s quad-core Bloomfield CPUs from posting higher scores still, though.

There’s not much to add here. The Thuban design is marginally faster than Deneb thanks to its extra two cores (and despite its clock rate deficit).

7. Benchmark Results: Media And Transcoding Apps

Our iTunes test is perhaps the most telling indicator of the effectiveness of Turbo CORE. We know that this application is not threaded, so we’d expect our 3.2 GHz Phenom II X6 1090T to ramp up to its maximum Turbo speed of 3.6 GHz.

The results, however, suggest that the 3.2 GHz part is merely matching the performance of AMD’s quad-core Phenom II X4 965. Meanwhile, everything from the sub-$200 Core i5-750 to the $1,000 Core i7-980X is able to outpace the two AMD chips.

Reiterating my previous point, Turbo CORE is compensating for the loss of clock speed resulting from AMD’s move to hexa-core computing without an accompanying die shrink. It does not look to improve performance versus the company’s previous flagship in single-threaded titles.

Of course, most media-oriented apps are not as handicapped as iTunes. MainConcept is well-threaded, so even if the X6 isn’t running as fast as the X4, it’s extra cores more than compensate, propelling the chip ahead of Intel’s quad-core Core i7-920 and -930, just behind the Core i7-975 Extreme. That’s a significant finish given the price gap between the -975, X6, and -930.

HandBrake, freely available, turns the tables even more in favor of AMD’s Thuban design. The Phenom II X6 1090T shaves more than two minutes off of the X4’s transcode, and AMD even manages to beat Core i7-975 by three seconds. Thuban can’t touch Gulftown, but again, we’re talking about the difference between a $295 and $1,000 processor here.

In the threaded DivX test, Phenom II X6 1090T again outperforms Intel’s quad-core Core i7-975, losing out only to Intel’s Core i7-980X. The Xvid routine isn’t threaded, though, and AMD’s X6 succumbs to the faster-clocked X4 part. The competition from Intel doesn’t do as well here.

It’s also interesting to note that, despite the fact that Intel’s six-core Gulftown part is bugged in Xvid, AMD’s six-core contender does not suffer from the same problem, and manages to complete the test without seizing up.

8. Benchmark Results: Productivity

Phenom II X6 1090T gets a big boost in our Photoshop CS4 test, but it’s only enough to pass Intel’s Core i5-750. The rest of the Bloomfield parts are still faster and Gulftown holds a more significant advantage. Nevertheless, compared to Phenom II X4 965, the six-core processor represents a massive speed-up.

I know I promised that AVG would disappear in my Core i7-980X review, but it’s making one final showing here, since my Kaspersky test isn’t ready yet. The results are unsurprising.

Threading optimizations in 3ds Max help the Phenom II X6 1090T shoot ahead of Intel’s Core i7-930, -920, and Core i5-750, while the Phenom II X4 965 trails in last place.

Five Intel processors dominate here, though threading clearly gives the X6 an advantage over AMD’s previous flagship.

Speed-ups in 7-Zip place AMD’s hexa-core CPU just behind Intel’s quad-core Core i7-975 Extreme Edition. The significance here, of course, is that the Phenom II X6 1090T beats out Intel’s Core i7-930—a slightly more expensive processor.

9. Benchmark Results: Crysis

Call it strange, but we ran and re-ran these tests. In fact, we formatted, started over, and got the same results. In Crysis, our Phenom II X6 1090T-based platform is simply slower than its quad-core predecessor—likely a result of its lower non-Turbo clock rate.

“But you’re clearly limited by your graphics card here,” you say. Alright, well, we’re using the 2010 reference system’s Radeon HD 5850, but let’s try something else. We’ll drop a Radeon HD 5870, a 5970, and a GeForce GTX 480 in the 1090T-based platform and see how much performance a faster card buys.

Amazing—the “fastest” card performs least-impressively, even at 1920x1080 and High quality settings. This is a combination we’d expect to hit the graphics fairly hard, but something is still screwy on the Phenom II X6 1090T-based platform. Now it looks less like our Radeon HD 5850 was holding back performance and more like the processor or platform is to blame.

Let’s try something else. Using a GeForce GTX 480, we’ll compare the performance of a stock Phenom II X6 1090T and a stock Core i7-930, then overclock the former to 3.7 GHz and the latter to 3.66 GHz (both processors with Turbo enabled). We’d expect to see headroom open up if there’s a bottleneck hampering performance.

Lo and behold, even with the fastest single-GPU card you can buy, the Phenom II X6 doesn’t spring to life. Meanwhile, the overclocked Core i7 leaps forward by quite a bit. This is eerily reminiscent of a gaming piece I wrote back in 2008 comparing high-end AMD and Intel gaming rigs. All else equal, the Phenom X4 I was testing at the time was simply creamed by Core i7 in Crysis.

This one gaming test opened up a ton of additional reformatting, reinstalling, and testing, just to make sure everything was reproducible. The conclusion we’re going to draw early on is that a six-core CPU running at a lower clock rate—Turbo CORE or not—is probably not the way to go for gamers. At any rate, onto Left 4 Dead 2.

10. Benchmark Results: Left 4 Dead 2

The fact that we’re seeing scaling based on CPU choice without anti-aliasing and fairly even performance with anti-aliasing is a good indicator that we’re bumping up against the performance of our Radeon HD 5850 once everything is cranked up.

But at 1680x1050, where the CPUs are demonstrating what they can do, it’s clear that the Intel CPUs have the advantage.

Of course, once you fire up the anti-aliasing or crank resolutions as high as 2560x1600, things normalize and it doesn’t matter which of these processors you pick—graphics determine performance.

11. Benchmark Results: Call Of Duty: Modern Warfare 2

Despite what we saw in the previous two games, Call of Duty actually seems to favor AMD’s architecture by a bit. The gap between our fastest and slowest contenders isn’t large, so it’s likely that our Radeon HD 5850 is holding back performance at each quality setting. But it is worth noting that the Phenom II X6 1090T ends up on top for each one of the three resolutions.

12. Benchmark Results: DiRT 2

Tight groupings in DiRT indicate that our Radeon HD 5850 is tuckered out. In the interest of seeing what more the Phenom II X6 1090T has to give, we dropped four other graphics cards into the platform to gauge performance.

Jumping up to a GeForce GTX 480 or Radeon HD 5970 helps some, but there’s still a ceiling in play here. We overclocked the Phenom II X6 to 3.7 GHz and managed to get 62.2 FPS without AA and 62.0 FPS with 4xAA enabled, but it’s still looking like the platform, rather than graphics, are holding us back on this one.

13. Power Consumption

At idle, the Phenom II X6 1090T results in slightly higher system power than the Phenom II X4 965. Under the load of Prime95, we also see somewhat higher energy usage numbers.

Compare those figures to Intel’s, though. Under load, the Phenom IIs generate comparable system power draw. But at idle, AMD’s Phenom II CPUs use quite a bit less.

Of course, these are snapshots at the top and bottom of each processor’s range. The more realistic measure of consumption comes from our exploration into Turbo CORE on page three, where we determined that, despite its additional complexity and Turbo CORE technology, the Phenom II X6 1090T only averages a few watts higher power use in a logged PCMark Vantage run.

14. Conclusion

Intel’s Core i7-980X gave us a six-core processor running at the same speed as its predecessor with a shared L3 cache increase to boot—and all at the same price point. Unfortunately, at $1,000, it’s still hard for most folks to get excited about hexa-core computing. If you can afford a grand, great. The -980X remains the fastest desktop processor available, and it sells at the same price as the quad-core -975. Choosing between the two is a no-brainer.

AMD took a different approach, adding cores (and corresponding L1/L2 cache), but leaving the shared L3 at 6MB. The addition of Turbo CORE shoots to emulate what Intel achieves through Turbo Boost, but it’s effectively Cool’n’Quiet in reverse, and arguably not nearly as elegantly implemented. Moreover, a $100 price increase means you’ll be paying more for AMD’s six-core solution.

But the Phenom II X6 1090T costs $295 to the Phenom II X4 965’s $185. This is a six-core CPU most of us can actually afford. The question is: who should spend the extra money?

Four Or Six?

The benchmarks speak volumes in this story. The moves from one to two cores and two to four were each met with slight clock rate drops, conceding to the increased complexity of doubling execution resources. Each step of the way, gamers actually saw better performance from the higher-clocked one- or two-core processors, while the folks using threaded software watched performance spring forward thanks to parallelism.

It might have been a fluke that Intel was able to time its 32 nm die shrink with the launch of its six-core Gulftown, but that was actually the first time I can remember that no compromises were made in increasing core count. AMD doesn’t have that luxury. The addition of low-k dielectric material in the metal layers almost amazingly facilitates a six-core design within AMD’s 125W TDP, but it’s not enough to kick the clocks up another notch.

As a result, it’s easy to recommend the Phenom II X6 1090T for folks able to employ its six cores. Video work, threaded Photoshop filters, rendering—in those workloads, AMD’s new flagship is, in many cases, able to keep up with the quad-core Core i7-975.

In the same vein, the gaming benchmarks are a reminder that the latest and greatest graphics cards really do need a capable processor behind them if you want to unleash their potential. An overclockable CPU like the Core i7-920 or -930 can really open up a Radeon HD 5870 or GeForce GTX 480 when you get it up to the 4 GHz range. Dipping down to 3.2 GHz doesn’t really help the 1090T win any battles in the games (Call of Duty excepted, where Turbo CORE seems to improve performance over the X4 965). If you’re a gamer, save the money you’d spend on a six-core CPU, buy your favorite overclockable processor, and spend the difference on graphics or an SSD to cut level load times.

AMD’s hexa-core Phenom II X6 1090T is decidedly a productivity-oriented part designed to improve the performance of threaded apps. It extends the usefulness of Socket AM3 until Bulldozer emerges in 2011. As a result, your 790FX-based motherboard will do the job just fine—it’s probably not worth upgrading to 890FX at this point. Turbo CORE is conceptually a good answer to Turbo Boost, but I had a hard time proving its effectiveness in the real-world. Best-case, it helped the 3.2 GHz 1090T keep pace with the 3.4 GHz 965 in single-threaded titles.

Perhaps the most impressive point from this launch is the fact that AMD is increasing core count by 50%, transistor count by just under 30%, and maintaining the same 125W of its fastest quad-core CPU. It’s almost a shame that price increases by more than 50% at the same time. Fortunately, there are plenty of heavily-threaded workloads that justify a sub-$300 six-core CPU.

Update: AMD just let me know that Tigerdirect.com is offering a $50 mail-in rebate on both the 1090T and 1055T processors. This improves both processors' values significantly, but especially makes us think long and hard about the Phenom II X6 1055T, which can now be had for less than the Phenom II X4 965, our real benchmark in this story. For as long as the Tiger deal lasts, its savings add quite a bit more impact to AMD's hexa-core launch.

Update2: Looks like the plug has already been pulled on the Tigerdirect.com rebate.