Although it has only been a few weeks since the launch of the capable Phenom II processor, AMD is back with an exciting new revision. This time, we’re not looking at quite the same Phenom II, but rather the DDR3-compatible socket AM3 Phenom II.
Although AM3 may sound like a completely new socket and architecture, AMD has graciously added a dose of backwards compatibility. Not only can these new AM3 processors be used in DDR3-compatible boards, but they work just as well in today’s wide variety of socket AM2+ motherboards. If Intel is not already taking note, we suggest they do so. This is one very good way to keep customers.
Although manufacturers are still working on AM3 motherboards, AMD was kind enough to provide two of their new AM3 processors for a preview of how they operate on today’s assortment of DDR2-based 790GX motherboards. Readers interested in DDR3 performance will have to wait for the availability of AM3 mainboards, but you can be sure that you’ll find those tests here when that time comes.
Without further ado, let’s have a look at these two new processors.
Detail and Specifications
The new AM3 Phenom II processors share many similarities with the early Phenom II models released back in January. As such, this preview primarily covers the architectural differences between the two models. Readers interested in learning more about their common architecture should read our Phenom II launch review.
Let’s take a closer look at the AM3 Phenom II and see what makes it unique.
Common AM3 Processor Specifications:
- L1 Cache Sizes: 64K of L1 instruction and 64K of L1 data cache per core (512KB total L1 per processor)
- L2 Cache Sizes: 512KB of L2 data cache per core (2MB total L2 per processor for X4s / 1.5MB total L2 per processor for X3s)
- L3 Cache Size: 4MB or 6MB (shared)
- Memory Controller Type: Integrated 128-bit wide memory controller *
- Memory Controller Speed: Up to 2.0GHz with Dual Dynamic Power Management (all current AM3 processors)
- Types of Memory Supported: Support for unregistered DIMMs up to PC2 8500 (DDR2-1066MHz) -AND- PC3 (DDR3-1333MHz)**
- HyperTransport 3.0 Link: One 16-bit/16-bit link @ up to 4.0GHz full duplex (2.0GHz x2)
- Total Processor Bandwidth: Up to 33.1 GB/s total bandwidth
- Packaging: Socket AM3 938-pin organic micro pin grid array (micro-PGA)
- Fab location: Fab 36 wafer fabrication facilities in Dresden, Germany
- Process Technology: 45-nanometer DSL SOI (silicon-on-insulator) technology
- Approximate Transistor count: ~758 million (45nm)
- Approximate Die Size: 258 mm2 (45nm)
- Max Ambient Case Temp / X4 CPUs: 71o Celsius
- Max Ambient Case Temp / X3 CPUs: 73o Celsius
- Max TDP: 95 Watts (all current AM3 processors)
*Note: MC configurable for dual 64-bit channels for simultaneous read/writes
**Note: for DDR3-1333, AM3 boards will support 1-DIMM-per-channel @ 1333MHz
There are several notable differences between the original Phenom II processors and the new AM3 models. First and foremost, we see that some of the AM3 processors will be outfitted with only 4MB of L3 cache. Since the transistor count is constant between both the 4MB and 6MB models, we can deduce that part of a 6MB processor was simply disabled to create the 4MB model. We’d encourage anyone interested in learning more about AMD’s stance on disabling CPU components to read our X3 review from last year.
The second thing we immediately noticed was the increased frequency of both the HyperTransport link and the memory controller. The HT link speed has increased one full multiplier to 2GHz (4GHz full-duplex) and the memory controller frequency has also been bumped from 1.8Ghz to 2.0GHz. Almost all Phenom processors –- with the exception of the 9950 Black Edition –- operate at a 1.8GHz memory controller clock speed. Although very minimal gains were seen with the first generation Phenom processor, the expected increase in memory bandwidth due to DDR3 support may take better advantage of this faster memory controller. We’ll see what kind of difference these frequency increases can make with our DDR2 tests today.
Naturally, the biggest selling point is support for both DDR3 and DDR2 memory. Official DDR2 support remains at PC2-8500 (1066MHz), but DDR3 frequencies are supported up to 1333MHz natively.
AMD is launching all of the above processors as of February 9. Three of the models will be available in “PIB,” or “Processor In Box,” variety at just about all PC part retailers. The X4 910 and X4 805 are launching as OEM parts and will likely find their way into pre-built systems from various manufacturers. Of all the processors, the most interesting is the “Black Edition” X3 720. At a relatively high 2.8GHz and the full 6MB of L3 cache available, it has the paper potential to be quite the enthusiast chip.
At launch, we’ll see the X4 810 retailing for about $175, which is significantly cheaper than the X4 920 and X4 940 processors on the market today. Even more enticing is the $145 launch price of the 2.8GHz X3 720 Black Edition. AMD is clearly pitting this processor up against Intel’s E8400 processor which costs about $20 more at the time of writing. At first blush, this is a very aggressive price tag that really puts Intel in an interesting spot. We’ll be throwing an E8400 processor into the ring for today’s testing to see how this new triple core part compares.
Here are the requisite CPU-Z shots of each CPU:
CPU-Z 1.49 is able to identify the AM3 processors correctly. Notice the higher HT link speed and 4MB of L3 cache.
The X3 720 enjoys a higher clock speed and all of its L3 cache, although one core has been disabled for a total of three functional cores. Again, the HT frequency is utilizing a 10x multiplier for a 2000MHz effective frequency.
As you can see above, the memory controller clock speed has also increased to 2000MHz with both the X3 720 and X4 810.
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