AMD Phenom II X4 940

AMD Phenom II X4 940
(Enter The Dragon)

AMD has been fighting an uphill battle on two fronts for the last few years. For a time, fierce competition from NVIDIA, coupled with some of their own problems executing, put the ATI graphics division in a deep hole. And ever since the introduction of the original Core 2 processors, and more recently the Core i7, AMD's processor division has fallen well behind Intel in terms of overall performance.Starting in November of 2007 though, we got a sense that AMD was slowly, but surely, clawing its way back into the fight. It began with the introduction of the Spider platform, which consisted of AMD's native quad-core Phenom processors, 7-series chipsets, and 3800-series graphics cards. Individually, the components that made up the Spider platform weren't performance leaders in their respective categories, but ultimately the platform proved to be solid, and of course, it was priced very competitively. The introduction of Spider also marked the first time AMD could offer an entire desktop platform consisting only of AMD-branded processors, core logic, and graphics.As many of you know, AMD hasn't been sitting idle since the Spider platform introduction. The company's chipset division has launched a handful of new chipsets, featuring one of--if not--the best IGPs on the market and a new Southbridge, the SB750, that allows for higher overclocks through the use of ACC, or Advanced Clock Calibration. The ATI graphics division has also been firing on all cylinders lately, having released a top to bottom lineup of GPUs that compete very favorably at their respective price points. AMD also recaptured the 3D performance crown from NVIDIA for a time with the Radeon HD 4870 X2. AMD wasn't going down without a fight.With the chipset and graphics divisions on a roll, it was time for the CPU team to pull the trigger on something new and exciting, to complete the new platform trifecta. It took some time, but that's exactly what's happening today. The end result is the Dragon platform which consists of new 45nm Phenom II X4 processors, 7-series chipsets, and ATI Radeon 4000 series graphics cards. We've got the goods in house and will fill you in on all of the juicy details on the pages ahead; for now let's get some of the particulars and back-story out of the way...

Although the Dragon platform as a whole is new, most of its parts have already been on the scene for quite some time now. As such, we have already covered them in-depth here on HotHardware, so we won't do the same again here. We will, however, recommend taking a look at a few past articles to get familiar with some of the underlying technology and components that partially comprise the Dragon platform.
The Radeon HD 4800 series articles detail the features and technology that have made them so successful in the 3D graphics space. And the various 7-series chipset, Phenom and Athlon processor, and Spider platform related articles cover the remainder of the platform--with the exception of the Phenom II that is, which we'll show you next.


AMD's new baby is the Phenom II X4 line-up of desktop processors. Like the original Phenoms that came before it, the new Phenom II X4 processors feature a native quad-core design, with a shared L3 cache, and they fit into current AM2+ sockets. There are quite a few changes under the hood, however, that give Phenom II processors a significant edge is power efficiency and performance over their predecessors, and there are more changes to come in the not too distant future.



The most significant change brought forth with the Phenom II X4 is AMD's use of a 45nm fabrication process to manufacture the chips. The transition to 45nm helped reduce power consumption somewhat, but has also allowed AMD to up the L3 cache to 6MB, while simultaneously shrinking the die to 258mm2 (65nm Phenoms are 285mm2). In addition to the 45nm switch, AMD also re-architected the execution cores to offer higher IPC through enhancements to the architecture, brand predictors, and remapping of the cores within the die. According to AMD, the changes made to the cache and execution cores offer up to 5% and 3% performance improvements, respectively, over the original Phenom design.Also new to the Phenom II X4 series is a DDR2 and DDR3 compatible integrated memory controller. The first batch of Phenom II processors, like the ones we're looking at today, however, will only work with DDR2 memory. Finally, the new Phenom II X4 processors will be offered at higher frequencies than existing models. The Phenom II X4 920 and 940 we'll be showing you here are clocked at 2.8GHz and 3.0GHz, respectively. The 940 also happens to be a "Black Edition" processor, that ships with unlocked multipliers, for easier overclocking.Speaking of overclocking, AMD has been touting the frequency headroom in these new processors from quite some time. In fact, at a recent event, we saw one overclocked to over 5GHz--a vast improvement over the 65nm Phenoms. We didn't quite get our sample to go that high, but still hit some respectable numbers. More on that on the next page.


As we've already mentioned, the first two Phenom II X4 processors to be introduced will use the same AM2+ packaging as existing Phenom processors. That means these new chips will be compatible with existing DDR2 platforms, after a BIOS update of course. Future Phenom II processors will employ AMD's socket AM3, which will usher in support for DDR3 memory.We should note, that future AM3-based Phenom II X4 processors will be backwards compatible with AM2 and AM2+ platforms, and work with DDR2 or DDR3 memory types. But these current AM2+ Phenom II X4 processors will not be forward compatible with AM3/DDR3 platforms.

As we showed you on the previous page, the new Phenom II X4 processors look just like the original Phenoms, or older Athlons for that matter. But we fired up the latest version of CPU-Z to take a look at our Phenom II X4 940 processor's inner workings, because there are some distinct differences with the underlying technology.

CPU-Z correctly identifies the processor as a Phenom II, based on the core codenamed "Deneb". As the information shows, the chip is manufactured using AMD's 45nm process technology and our particular sample has a stepping designation of 2 and revision of RB-C2. The chip is clocked at 3GHz, due to its 15x multiplier and 200MHz base clock, the HT link is running at 1.8GHz, and there is 512K of L1 Data / Instruction cache, 2MB of L2 cache (512K per core), and 6MB of shared L3 cache.

With all of the information AMD has already revealed regarding the Phenom II's overclockability, we were eager to see what our particular chip could do. We didn't use any exotic cooling for our overclocking experiments, opting instead to see just how far the chip would go with a stock AMD PIB air cooler installed. With only a minor bump in voltage to 1.575v, we were able to take our particular CPU to almost 3.8GHz using the stock air cooler alone. That speed was achieved with an 18.5x multiplier and a 202MHz base clock; the components were installed in a basic mid-tower. The AMD Overdrive utility shown in the screenshot above did not report clock speeds correctly, but assuming thermal readings were correct (we don't think they were), the chip ran at about 50'C while overclocked.

How We Configured Our Test Systems: When configuring our test systems for this article, we first entered their respective system BIOSes and set each board to its "Optimized" or "High performance Defaults". We then saved the settings, re-entered the BIOS and set memory timings for either DDR2-1066 (AMD) with 5,5,5,15 timings or DDR3-1333 with 7,7,7,20 timings (Intel). The hard drives were then formatted, and Windows Vista Ultimate was installed. When the Windows installation was complete, we updated the OS, and installed the drivers necessary for our components. Auto-Updating and Windows Defender were then disabled and we installed all of our benchmarking software, defragged the hard drives, and ran all of the tests.

The various SiSoft SANDRA tests we ran paint the Phenom II X4 940 in a somewhat favorable light. The chip was the fastest of all of the AMD-based systems by bar, and it held its own against the similarly clocked, Penryn-based Intel Core 2 Quad Q9650, although the Q9650 was faster overall. The Core i7-based systems simply extended the lead held by the Core 2 Quads.In the memory bandwidth tests, the Phenom II X4 940 offered up 12GB/s of bandwidth with DDR2-1066 memory attached. It's going to be interesting to see how that numbers changes when the DDR3-enabled AM3 editions of these processors are released later this year, with potentially higher frequencies.

We ran a handful of processors and platforms, including the new Phenom II X4 940 and 920, through Futuremark’s latest system performance metric built especially for Windows Vista, PCMark Vantage. PCMark Vantage runs through a host of different usage scenarios to simulate different types of workloads including High Definition TV and movie playback and manipulation, gaming, image editing and manipulation, music compression, communications, and productivity. Most of the tests are multi-threaded as well, so the tests can exploit the additional resources offered by a quad-core CPU.

AMD's new Phenom II X4 940 and 920 processors performed very well in PCMark Vantage. The most interesting comparison is between the similarly clocked 3.0GHz Q9650 and the X4 940. In a direct comparison, the Core 2 Quad Q9650 outperforms the Phenom II in the the Music and Memories tests. The Gaming test was a virtual tie between the two, and the Phenom II takes the rest. The Phenom II holds its own against the Core i7 920 in a few tests too, but gets smoked in the gaming test.

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