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AMD's AM3 CPUs: Phenom II X4 810 and Phenom II X3 720 Black Edition
February 08, 2009 Brandon Sandman Bell

Summary: A month after launching Phenom II, today AMD is introducing five new AM3-based Phenom II CPUs. The new processors boast lower price tags and an improved 2.0GHz memory controller. But how do they perform and overclock? Find out in this article!


AMD’s AM3 CPUs: Phenom II X4 810 and Phenom II X3 720 Black EditionPage:: ( 1 / 11 )

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AMD is trying to ramp their new 45-nm manufacturing process as aggressively as possible, even if that means they have to take a hit on existing 65-nm Phenom processors in the process. Phenom has never been a hot seller for AMD anyway, and all indications are that Phenom II should address this. Already Phenom II has picked up numerous design wins, including Dell’s latest XPS 625 gaming PC. AMD’s new Phenom II CPUs deliver improved performance over their predecessors, run cooler, and are cheaper for AMD to manufacture. In the end it makes sound business sense for AMD to sweep out the old parts as quickly as possible and bring in the new.

As a result, today AMD is launching five new AM3 processors. All of these chips are priced below $200, making them excellent values for the hardware enthusiast on a budget (and who isn’t nowadays). Cheaper CPUs is precisely what we asked for in the conclusion of our Phenom II X4 940 article, so it’s great to see AMD respond so quickly.

Despite their new AM3 interface, the processors are backward-compatible with AMD’s infrastructure of existing AM2+ motherboards and DDR2 memory. All you’ll need to do is update your motherboard’s BIOS, and you’ll be good to go. In addition, the CPUs are DDR3-ready for Socket AM3 motherboards, with DDR3 memory speeds up to 1333MHz fully supported.

Unfortunately, the new AM3 processors aren’t clocked as high as their AM2+ counterparts launched last month, with speeds topping out at just 2.6GHz for quad-core models, but they do correct one minor gripe we had with the AM2-based Phenom II 920 and 940: memory controller and HyperTransport speeds. The integrated memory controller (MC) and HyperTransport (HT) link in the Phenom II 920 and 940 CPUs were limited to speeds of 1.8GHz, whereas previous Phenom 9850 and 9950 CPUs boasted speeds of up to 2.0GHz for the MC and HT link.

AMD’s AM3 Phenom II CPUs correct this issue, fully supporting memory controller and HyperTransport speeds of 2.0GHz. In addition, the new AM3 CPUs all boast a TDP of just 95W, making them more energy efficient than their predecessors.

So what’s launching today? Have a look at the following chart:

AMD Phenom II Lineup
Phenom II X4 940 Black EditionPhenom II X4 920Phenom II X4 910Phenom II X4 810Phenom II X4 805Phenom II X3 720 Black EditionPhenom II X3 710
Clock Speed3.0GHz2.8GHz2.6GHz2.6GHz2.5GHz2.8GHz2.6GHz
L1 Cache Size64KB instruction+64KB data per core (512KB per CPU)64KB instruction+64KB data per core (512KB per CPU)64KB instruction+64KB data per core (512KB per CPU)64KB instruction+64KB data per core (512KB per CPU)64KB instruction+64KB data per core (512KB per CPU)64KB instruction+64KB data per core (512KB per CPU)64KB instruction+64KB data per core (512KB per CPU)
L2 Cache Size512KB per core (2MB total per CPU)512KB per core (2MB total per CPU)512KB per core (2MB total per CPU)512KB per core (2MB total per CPU)512KB per core (2MB total per CPU)512KB per core (1.5MB total per CPU)512KB per core (1.5MB total per CPU)
L3 Cache Size6MB (shared)6MB (shared)6MB (shared)4MB (shared)4MB (shared)6MB (shared)6MB (shared)
Memory ControllerIntegrated 128-bit wide memory controllerIntegrated 128-bit wide memory controllerIntegrated 128-bit wide memory controllerIntegrated 128-bit wide memory controllerIntegrated 128-bit wide memory controllerIntegrated 128-bit wide memory controllerIntegrated 128-bit wide memory controller
Memory Controller Speed1.8GHz with Dual Dynamic Power Management1.8GHz with Dual Dynamic Power Management2.0GHz with Dual Dynamic Power Management2.0GHz with Dual Dynamic Power Management2.0GHz with Dual Dynamic Power Management2.0GHz with Dual Dynamic Power Management2.0GHz with Dual Dynamic Power Management
Memory Types SupportedSupport for unregistered DIMMs up to PC2 8500 (DDR2-1066MHz)Support for unregistered DIMMs up to PC2 8500 (DDR2-1066MHz)Support for unregistered DIMMs up to PC2 8500 (DDR2-1066MHz) and PC3-10666 (DDR3-1333MHz)Support for unregistered DIMMs up to PC2 8500 (DDR2-1066MHz) and PC3-10666 (DDR3-1333MHz)Support for unregistered DIMMs up to PC2 8500 (DDR2-1066MHz) and PC3-10666 (DDR3-1333MHz)Support for unregistered DIMMs up to PC2 8500 (DDR2-1066MHz) and PC3-10666 (DDR3-1333MHz)Support for unregistered DIMMs up to PC2 8500 (DDR2-1066MHz) and PC3-10666 (DDR3-1333MHz)
HyperTransport 3.0 LinkOne 16-bit/16-bit link @ up to 3.6GHz full duplex (1.8GHz x2)One 16-bit/16-bit link @ up to 3.6GHz full duplex (1.8GHz x2)One 16-bit/16-bit link @ up to 4.0GHz full duplex (2.0GHz x2)One 16-bit/16-bit link @ up to 4.0GHz full duplex (2.0GHz x2)One 16-bit/16-bit link @ up to 4.0GHz full duplex (2.0GHz x2)One 16-bit/16-bit link @ up to 4.0GHz full duplex (2.0GHz x2)One 16-bit/16-bit link @ up to 4.0GHz full duplex (2.0GHz x2)
Total Processor Bandwidth31.5 GB/s31.5 GB/s33.1 GB/s33.1 GB/s33.1 GB/s33.1 GB/s33.1 GB/s
PackagingSocket AM2+ 940-pin organic micro pin grid array (micro-PGA)Socket AM2+ 940-pin organic micro pin grid array (micro-PGA)Socket AM3 938-pin organic micro pin grid array (micro-PGA)Socket AM3 938-pin organic micro pin grid array (micro-PGA)Socket AM3 938-pin organic micro pin grid array (micro-PGA)Socket AM3 938-pin organic micro pin grid array (micro-PGA)Socket AM3 938-pin organic micro pin grid array (micro-PGA)
Nominal Voltage0.875 - 1.5V0.875 - 1.5V0.875-1.425V0.875-1.425V0.875-1.425V0.850-1.425V 0.875-1.425V
Max Ambient Case Temp62 degrees Celsius62 degrees Celsius71 degrees Celsius71 degrees Celsius71 degrees Celsius73 degrees Celsius73 degrees Celsius
Max TDP125W125W95W95W95W95W95W
Price$225$195Available in tray only$175Available in tray only$145$125


Notes

As you can see, besides introducing a new 910 model number clocked at 2.6GHz, AMD is also launching two new 800-series quad-core parts, the 2.6GHz 810 and the 2.5GHz 805, as well as two new triple-core Phenom II X3 models: the 720 Black Edition and the 710 clocked at 2.8GHz and 2.6GHz respectively. The new 800-series parts ship with less L3 cache than their 900-series counterparts -- 4MB of L3 versus the 6MB L3 found on the 900-series parts, but otherwise they’re similar.

Surprisingly enough, the triple-core parts ship with the same 6MB of L3 cache as AMD’s 900-series CPUs, this makes them a compelling value if you primarily deal with single and dual-threaded apps given their sub-$150 price tags and relatively high clock speeds (if you recall, AMD’s Phenom X3 8750 topped out at just 2.4GHz).

Unfortunately we don’t have pricing on AMD’s 910 and 805 models at the time of writing, although you can always check out AMD’s processor pricing page for the latest info.


L3 Cache Size and PerformancePage:: ( 2 / 11 )

To see the performance impact of the Phenom II X4 810’s smaller L3 cache, we ran benchmarks of the CPU paired against an underclocked Phenom II 940 as well as the original Phenom 9950. We know, it isn’t an exact apples-for-apples comparison since the 940 utilizes a slower HT link and memory controller but it’s the closest we could get for testing:

Gaming






Notes

When compared against the underclocked Phenom II 940 running at 2.6GHz, the X4 810 and its smaller L3 cache doesn’t lose as much performance as we initially expected. Performance drops less than 1% in Crysis, while Far Cry 2 and World In Conflict ran 3% and 4% slower on the 810’s 4MB L3 cache versus the 6MB 940. Lost Planet showed the biggest drop at 5%.

We also included test results with the Phenom 9950, although keep in mind that AMD has incorporated enhancements into the Phenom II parts that improve IPC, so it isn’t an apples-to-apples comparison.


Media benchmarks






Notes

MP3 encoding with LAME is highly dependant on the CPU’s clock speed, so we honestly weren’t surprised to see the two Phenom II CPUs pull even in this benchmark. Seeing Cinebench results within the margin of error was a bit of a surprise though, the two processors are practically dead even here too. We did manage to shave 2 seconds off our DivX conversion testing with the 6MB cache found on the underclocked 940 processor, and the Valve particle simulation benchmark also ran 3% faster than the 810.




AM3 Motherboards/OverclockingPage:: ( 3 / 11 )

To test out the performance of their new AM3 processors, AMD sent us two CPUs from today’s launch: the Phenom II X4 810, and the triple-core Phenom II X3 720 Black Edition. The 810 is targeted towards the user who needs four processing cores but doesn’t want to pony up the cash for a 910 or 920 CPU, while the X3 720 is obviously positioned towards users who don’t necessarily need four cores and want to save even more money.

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Physically the new AM3 CPUs look similar to their AM2+ counterparts, although obviously the new AM3 parts have two fewer pins on the underside of the processor. Since AMD hasn’t moved to pin-less packaging for their desktop processors just yet, fewer pins is obviously a good thing. The backward compatibility also makes it easier for do-it-yourselfers who picked up a 790GX or 790FX motherboard with AMD’s newer SB750 South Bridge last year who wish to upgrade to AMD’s latest processors.

Not everyone has an AM2+ motherboard though, or perhaps you want to squeeze every ounce of performance out of your AM3 CPU and wish to upgrade to faster DDR3 memory. For these users, you’ll want to upgrade to the latest AM3 motherboard and DDR3-1333 (or better) memory.

AM3 Motherboards

So far ASUS, Gigabyte, and MSI have announced AM3 motherboards, with all three manufacturers offering multiple AM3 options. ASUS has announced the most AM3 SKUs to date, with their M4A78 and M4A79 series comprising of four motherboards. The M4A79T Deluxe is AMD’s flagship offering and is based on AMD’s 790FX+SB750 combo, while the M4A79 Deluxe supports DDR2 memory. For integrated platforms ASUS offers the M4A78 Pro, which is based on AMD’s 780G chipset. Finally, the M4A78-E utilizes 790GX.

Like the M4A79T, Gigabyte’s GA-MA790FXT-UD5P is built around AMD’s 790FX chipset with SB750 South Bridge, and offers multiple DDR3 speeds beyond 1333MHz. The GA-MA790XT-UD4P is the first 790X motherboard to support AM3, with support for CrossFireX and hopefully lower pricing than 790GX motherboards.

Finally there’s MSI. MSI’s also announced two AM3 motherboards. The 790FX-GD70 is their 790FX+SB750 offering for enthusiasts. DDR3 speeds up to 2133MHz are available within the board’s BIOS. For mainstream users MSI offers the 790GX-G65, which relies on AMD’s 790GX chipset with DDR3 speeds topping out at 1600MHz.

For the sake of our sanity, we’re holding off on AM3 motherboard testing until the motherboard manufacturers have had more time to fine tune their BIOS’ for the new AM3 CPUs and DDR3 memory. Even existing AM2+ boards have had some last minute BIOS adjustments for AM3 CPUs, so rather than troubleshoot issues with AM3 boards, we’ve decided to play it safe and stick with just AM2+ testing for now.

For the record, AMD has stated that DDR3-1333 should improve performance by up to 5% under the right conditions.


Overclocking

With AMD baking in enhancements into their new 45-nm manufacturing process, we were eager to see how far we could push our latest Phenom II CPUs utilizing the AM3 socket. With its unlocked clock multiplier and one fewer core, we were particularly curious to see how far we could push the Phenom II X3 720 Black Edition. It didn’t disappoint.

At stock voltage levels, we were able to hit speeds of 3.03GHz, with the multiplier at 13.0x and the HT link speed of 233.6.

With the voltage cranked up to the max of 1.55V, we were able to hit speeds of 3.8GHz. That’s actually slightly higher than the 3.745GHz we hit with our Phenom II X4 940 sample a month ago.

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We could actually boot up some apps at even higher speeds, but couldn’t maintain stability. Windows Vista would BSOD at the splash screen at 4GHz.

We didn’t manage to have the same luck with our Phenom II X4 810 sample, but it wasn’t due to the fault of the CPU itself, rather we’re chalking it up to a software issue. Unfortunately for whatever reason AMD’s Overdrive tool wouldn’t allow us to crank up the CPU voltage beyond 1.325V, and when we attempted to dial in higher voltages manually via the BIOS of our motherboard (an ASUS M3A78-T), the motherboard failed to POST. Even if we cranked the HT link speed up just 5MHz with higher voltage. In fact, our Western Digital hard drive would make a clicking noise as if it were about to fail.

So armed with no way to adjust voltage, our X4 810 maxed out at 3.1GHz. That’s actually a little higher than the speed we hit with the X3 720 at stock volts, and it’s also a 500MHz OC, but we can’t help but wonder what kind of potential is lying untapped in this particular sample. 3.9GHz perhaps? While it had no problems with the X3 720 BE, the ASUS BIOS is likely having problems picking up the 810.

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Besides the AM3 processor and ASUS M3A78-T mobo, we also used Zalman’s all-copper CNPS 9700-Cu CPU cooler along with Antec Formula 5 silver paste, OCZ Platinum RAM and Windows Vista Ultimate 64-bit. Keep in mind that 32-bit operating systems tend to OC further than 64-bit.



System SetupPage:: ( 4 / 11 )

Intel Core 2 Quad Q9400
Intel Core 2 Quad Q6600
Intel Core 2 Duo E8400

ASUS P5E3 Premium

4GB (4x1GB) OCZ DDR3 PC3-16000 Platinum

AMD Athlon X2 6000+
AMD Phenom X4 9950 Black Edition
AMD Phenom X3 8750 Black Edition
AMD Phenom II X4 940 Black Edition
AMD Phenom II X4 920
AMD Phenom II X4 810
AMD Phenom II X3 720 Black Edition

ASUS M3A78-T (790GX)

4GB (4x1GB) OCZ DDR2 PC2-8500 Platinum

NVIDIA GeForce GTX 295
ForceWare 181.20

500GB Western Digital Caviar SE16

Windows Vista Ultimate 64-bit w/Service Pack 1


Benchmarks

Lost Planet
World In Conflict
Crysis
Far Cry 2




Media Encoding/Rendering BenchmarksPage:: ( 5 / 11 )








Valve Particle Simulation Benchmark







World In Conflict PerformancePage:: ( 6 / 11 )

World In Conflict – Direct3D






Far Cry 2Page:: ( 7 / 11 )

Far Cry 2 – Direct3D







CrysisPage:: ( 8 / 11 )

Crysis – Direct3D







Lost PlanetPage:: ( 9 / 11 )

Lost Planet – Direct3D







OverclockingPage:: ( 10 / 11 )















ConclusionPage:: ( 11 / 11 )


Given the state of today’s economy, everyone’s looking at ways to maximize their money. Whether it’s clipping coupons, buying generic, or simply going out less, we’re all finding ways to trim our budgets. In this economy, it’s all about affordable goods.

That’s why the low (sub-$200) pricing of AMD’s latest processors is so important. The Phenom II X4 810 is priced at just $175, making it cheaper than Intel’s venerable Core 2 Quad Q6600. And thanks to its 2.8GHz clock speed, the Phenom II X3 720 Black Edition performs like AMD’s more expensive Phenom II X4 920 in most of the apps we tested.

Only in applications that are specifically designed to stress four or more threads like Lost Planet, Cinebench, Valve’s particle simulation benchmark, and our DivX testing did we actually see the 920 outrun the X3 720. And with its unlocked clock multiplier it has tremendous potential for OC’ing.

Because of this, of all the processors AMD is launching today, it’s the Phenom II X3 720 Black Edition that has us excited the most. For less than $150 you can get a chip that outperforms more expensive quad-core parts in most games, as very few titles are coded to take advantage of more than two threads at a time to this day. That’s why many enthusiasts have opted to save their money and pick up a Core 2 Duo CPU based on Intel’s Woldale core like the E8400 we tested today. The E8400 outperformed the X3 720 in most of the games we tested, but in our media encoding/rendering tests the AMD triple-core CPU won 3/5 benchmarks, and the AMD processor costs about $20 less than the E8400 as well.

The Phenom II X3 720 Black Edition doesn’t kill the E8400, but given all this, it makes a very good competitor. That’s something AMD just couldn’t offer for most of last year. The backward compatibility with existing AM2+ motherboards is also great. For maximum bang for the buck, we recommend sticking with DDR2 though, as DDR3 memory prices are still considerably higher than DDR2.

Now we’re just waiting for AMD’s first AM3 parts to hit 3.0GHz. Hopefully we won’t have to wait long for this to happen, although online rumors suggest this won’t occur until sometime in Q2’09. We’ll cross our fingers and toes for something shorter…



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