The production of a sequel typically implies that the original creation is worth revisiting. However, considering that the original Phenom was the hardware version of Ishtar, many enthusiasts didn’t think Phenom deserved to be revisited.
AMD certainly thinks it does—and it hopes Phenom II is Star Trek II: The Wrath of Kahn to Phenom’s Star Trek: The Motion Picture. And why shouldn’t AMD be able to pull off a reversal of fortune? Phenom II isn’t just Phenom joined by a Roman numeral—it’s a die shrink with a boatload of additional cache and an improved core. In short, AMD hopes to erase memories of the original Phenom and put smiles on the faces of disappointed overclockers with its reimagined Phenom II chip.
Come with us as we review, critique, and dissect Phenom II and find out how it stacks up against a stack of Intel CPUs.
AMD’s trip back to the drawing board
The Phenom launch certainly didn’t go as AMD had planned. Rather than christening a new line that would change the company’s fortunes, AMD CEO Hector Ruiz broke a bottle of champagne over the bow of a ship that promptly sank under the waves—but only after smashing into a nearby pier with a bait shop and a busload of tourists on it: Phenom was a year late and had a performance-crippling TLB bug, yield issues, and a performance gap with Intel’s older generation of CPUs.
Fast-forward a year and the picture looks far different for the underdog chipmaker. Phenom II is actually ahead of schedule. And doubts about overclocking were quashed months ago when the company invited elite overclockers to its headquarters to get medieval on the new chip with liquid nitrogen and other exotic toys. The result? Overclocking feats beyond 5GHz.
Not to belabor the sequel talk, but it’s clear that AMD doesn’t intend for its pair of new Phenom II chips to be cheesy follow-up. These CPUs are intended to erase all doubts that the original chip created and help quell uneasiness about the company’s ability to make good parts.
The Dynamic Duo
The Phenom II family consists of two CPUs: the 2.8GHz Phenom II X4 920 and the 3GHz Phenom X4 940 Black Edition. Both use the company’s new 45nm process and can be paired with the majority of Socket AM2+ boards (and even some AM2 boards.) Both CPUs are native quad-core designs with all four execution cores residing on a monolithic die. AMD will continue its practice of repackaging defective quad-core dies as tri-cores (denoted with X3 rather than X4).
New under the Hood
For the most part, Phenom II isn’t a radical departure from Phenom. It has the same basic core and still features an integrated memory controller and HyperTransport connections for chip-to-chip connections. The update does include a few substantial changes, however. The biggest is the move to a 45nm process, which significantly shrinks the size of the chip and results in better yields; additionally, the 45nm-based Phenom II has 758 million transistors but is only 258mm2. The original 65nm Phenom has 450 million transistors and measures 285mm2.
By shrinking the die, AMD is able to use some of the freed up real estate for more cache. While the L1 and L2 remain unchanged, the L3 goes from 2MB in Phenom to 6MB in Phenom II. This larger cache is also slightly faster than the 65nm Phenom’s.
In other good news for enthusiasts, the new chip includes both a DDR2 and a DDR3 integrated memory controller. The bad news is that the first two Phenom II chips will support only DDR2; both DDR2 and DDR3 will be supported with its AM3 revision of Phenom II, which will be released in the next few months.
So why release a version of Phenom II that is limited to DDR2? AMD didn’t want to wait the additional months it would have taken to validate the CPUs for both newer DDR3 boards and DDR2 boards. The company felt that to have a Phenom II that runs at decent clock speeds, overclocks like crazy, and drops into existing boards is just a better way to prove its back on track.
More importantly, AMD doesn’t think people are that hot for DDR3 right now due to its premium price. To some extent, AMD is right: Two 2GB modules of DDR2/800 will set you back just $28, while a pair of 2GB DDR3/1333 modules costs about $100. However, true sticker shock sets in at the highest speeds: 4GB of DDR3/1600 costs about $300 and 4GB of DDR3/2000 will set you back about $400.
We would have preferred it if AMD had introduced one CPU that would work with both types of memory, but we understand that due to its position in the market, it simply doesn’t have the luxury of waiting three months to get Phenom II to work with both new DDR3 boards and the older DDR2 infrastructure.
But all you really want to know is whether Phenom II will work with your board, right? Minus the missteps with the original Socket 940 and Socket 754 nonsense (well, and QuadFX), AMD has worked hard to ensure that CPU swapouts won’t cause havoc. Phenom II will work in almost every board that supports the original Phenom CPU, with the only caveat being boards not designed to handle CPUs hotter than 95 watts. Since both Phenom II CPUs are 125 TDP chips, they likely will not work with those boards.
Cooler than Ever
While new manufacturing doesn’t always lead to more efficient parts, this die shrink certainly seems to have helped AMD with thermals. For example, the 65nm-based 2.6GHz Phenom X4 9950 BE had a thermal design power rating of 140 watts, while the 45nm-based 3GHz Phenom II X4 940 has a TDP of 125 watts.
AMD also seems to have finally shed the “cold bug” that frustrated extreme overclockers. The original Phenom would overclock to a certain level on air, but when extreme cooling techniques were applied, it wouldn’t overclock any further. While cold temperatures aren’t a cure-all, most CPUs offer additional headroom at -150 F. But the original Phenom simply hit a wall and no amount of cooling would allow for additional overclocking. AMD set out to prove it fixed this issue in Phenom II by hosting private demos for a group of extremes overclockers. Apparently, no one left the demo unhappy.
Every PC is essentially a CPU, a chipset, a GPU, and storage, so you may be confused when you hear the word “platform” thrown around like it’s some new type of technology. It’s not. It’s an artificial way Intel and AMD brand a set of components. For Intel, Centrino is simply the combination of the CPU, chipset, and a Wi-Fi chip. Laptops sold without those three key Intel ingredients are not allowed to use the Centrino sticker. Since Intel advertises the hell out of Centrino, not Core 2 Duo Mobile, most OEMs feel compelled to buy all three parts from Intel.
AMD is not being as Machiavellian with its platform (at least not today), but it is doing some branding around a Dragon theme. Dragon is a combination of the Phenom II, an ATI 790GX or ATI 790FX chipset, and a 4000-series Radeon HD GPU. Does this mean that you can’t use a GeForce GTX 295 with Phenom II? No. Everything is as it was before—you can probably even use the Phenom II 940 in some older AM2 boards with the original Nvidia 590 SLI chipset.
So why bother to push all this platform hooey? Today, it’s just a marketing gimmick, but tomorrow it may be far more meaningful. With the functionality of the chipset, CPU, and GPU morphing together, this collection of hardware may indeed be a platform that you buy in a few years. That’s one thing AMD likes to toot its horn about: Intel has CPUs and chipsets and Nvidia has GPUs and chipsets, but only AMD has all three ingredients.
CPU companies like to use mysterious model numbers that don’t tell you a damn thing about how their chips actually perform. One quick and dirty way to see what the company thinks of a particular chip is to look at its price. AMD’s pricing of Phenom II reveals where the company thinks the CPU will compete. For example, the current king of the hill, the Core i7-965 Extreme Edition, is priced at $999. AMD has priced the Phenom II X4 940 at $275, so you can see where the company expects the CPU to fall—it’s clearly not intended to take on Intel at the high end. AMD, however, thinks there’s plenty of room to compete in the midrange against Intel’s large stable of Core 2 Duo and Core 2 Quad parts.
We put the top-end Phenom II X4 940 against Intel’s top-end Core i7 part, the still-shipping top-end Core 2 Extreme Edition part, as well as a lineup of budget Intel and AMD CPUs. The upshot is that AMD fans can take Phenom II as a sign that the company has some magic left. While Phenom was Detroit Lions bad, Phenom II is maybe Oakland Raiders or Green Bay Packers bad. Yeah, it was an ugly season, but you can tell the team is on the right track.
Our Testing Method
For our Phenom II showdown, we used a 3GHz Phenom II X4 940 BE on an MSI DKA790GX board. AMD partisans pitched a fit when we conducted our Core i7 tests with the AMD Phenom X4 9950 BE using “just” DDR2/800 RAM—they believed it was a travesty that we didn’t run DDR2/1066. Truth is, the performance difference between DDR2/800 to DDR2/1066 is minimal. In fact, after we published our Core i7 tests we spoke with AMD representatives, who agreed that the small difference in memory bandwidth had virtually no impact on the beatdown Core i7 gave Phenom.
To keep the peanut gallery happy, we tested the Phenom II X4 940 BE with 4GB of DDR2/1066. For comparison, we used a 3.2GHz Core i7-965 Extreme Edition and a 3.2GHz Core 2 Extreme Edition QX9770. We downclocked these parts to simulate the performance of a 2.66GHz Core i7-920 and a 2.83GHz Core 2 Quad Q9550, respectively. We also included the 2.6GHz Phenom 9950 X4 BE in our tests.
For all the test runs, we used the same GeForce 8800 GTX card and Western Digital Raptor 150 hard drive. The Core 2, Phenom and Phenom II rigs featured 4GB of RAM, while the Core i7 machines had just 3GB of RAM. All tests were conducted using the 64-bit version of Microsoft Windows Vista Home Premium.
Our benchmarks reflect various levels of multithread rendering, video editing, encoding, and 3D rendering. Nvidia likes to say that quad-core CPUs are unimportant, but we’re finding a very strong and fast move by application vendors to support quad core where it’s needed. We didn’t feature any dual cores in our tests because they simply can’t compete against these opponents. However, the majority of today’s games exploit two cores at best, so to eliminate graphics as a bottleneck, we ran all of the games at very low resolutions, with all the eye candy turned off. We also ran a set of synthetic memory and scientific and application workload tests to get a balanced picture of how well these quad-cores perform.
If you’re an AMD fanboy expecting Phenom II to put its bootprint on the hind end of Core i7—any Core i7—prepare to be disappointed. The slowest 2.66GHz Core i7 920 beat the Phenom II by double digits in most of our tests. We saw differences from 11 percent to 27 percent in encoding, and in our WinRar test, the Core i7-920 was 35 percent faster. It wasn’t all bad news for Phenom II though. The chip won the ScienceMark 2.0, Quake 4, and PC Mark Vantage tests and eked out a win in the Valve map compilation test. However, we’re still calling this competition for the i7 920. Of course, the 920’s big brother, the 965 Extreme Edition, completely walked away from the Phenom II. AMD, however, isn’t concerned that its $275 chip can’t beat a $999 one—the company isn’t competing at the top end of the market. And even though the 920 is about $300, the price of a new i7 motherboard ($250) and three pieces of required DDR3 ($150) nullifies any performance benefit the i7 has, AMD claims.
AMD is far more interested in how Phenom II does against a Core 2 Quad. The Phenom II actually outscored the Core 2 Quad in our MainConcept encoding test, our ProShow Producer slideshow creation test, and Quake 4, and it just about broke even in our WinRar file compression test. The Core 2 Quad hit back in both 3DMark tests, Premiere Pro CS3, Photoshop CS3, and both of our Valve multithreading tests. Although the Phenom has a 167MHz advantage, we’d have to call this one a tie.
This again comes down to perspective. Intel fanboys can say, “Been there, done that” since AMD’s best CPU just barely pulls even with a chip family Intel introduced more than a year ago. But from AMD’s perspective, the Phenom II is a big deal. With a down economy, the company believes that people will be looking for performance on a budget, and if Phenom II supplies that without the need for a pricey new motherboard, it’s won half the battle.