When AMD released the Socket AM3 processors earlier this year, the 900-series was left out of the mix. We found the Phenom II X4 820 and Phenom II X3 710 to be pretty potent little chips, but the range topping 900-series chips, the Phenom II X4 920 and X4 940 Black Edition were stuck in the land of DDR2.
That time is over.
Today, AMD is releasing its new flagship processor, the Socket AM3 Phenom II X4 955. This new Phenom II is fully backwards compatible with AM2+ motherboards, but brings a DDR3 memory controller and a boost in clock speed over the previous top Phenom II, the X4 940 Black Edition. Also joining the Phenom II X4 955 BE is the Phenom II X4 945, a lower clocked and multiplier-locked version.
The new chip should hit shelves today priced at $245. This puts it at an awkward, but strategic position in the marketplace. Intel’s similarly priced Core 2 Q9450 was recently discontinued, so the chip has no direct competition at its price-point. Instead, it looks up Intel’s line to the Q9550, a $280 chip whose price nears that of the Core i7 920. AMD has set its sights high while keeping the price low enough that the chip doesn’t compete directly price-wise with the Nehalem.
AMD graciously sent the Phenom II X4 955 to us, along with a DDR3 motherboard and memory so we can test this update to the Dragon platform for ourselves. Unfortunately for today, MSI has not released a BIOS to support the new processor for our test bench, so we are unable to test its DDR2 performance. We did, however, secure a Q9550 for DDR2 and DDR3 comparison, giving us a look at how the processor performs compared to past models we’ve tested.
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: GLOBALFOUNDARIES Fab 1 module 1 in Dresden, Germany (formerly AMD Fab 36)
- 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 Temp Phenom II X4 955:62o Celsius
- Nominal Voltage: 0.875-1.5V
- Max TDP: 125 Watts
*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
The biggest difference between the early Phenom II AM3 processors and the new Phenom II X4 900-series models is the L3 cache. Quad core 800-series chips are outfitted with only 4MB of L3 cache. The new Phenom II X4 955 and 945 feature 6MB 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 biggest change side from cache is the increase in frequency. The Phenom II X4 955 is the fastest Phenom II offered to date with a clock speed of 3.2GHz. That’s only a 200mhz step up from the X4 940, so we hope to see just how much of a difference a little speed and DDR3 make for the chip.
Here are the requisite CPU-Z screenshots for the Phenom II X4 955.
Also, for comparison sake, here are screenshots for its opponent today, the Q9550 in both DDR2 and DDR3 environments.
Despite being clocked lower, the Q9550 packs 12MB of L2 cache.