AMD Phenom II X4 940 Review :: Phenom II X4 Features

• 45nm
• Deneb architecture
• 285mm2
• 758 million transistors
• AM2+/AM3
• DDR2-1066MHz Support/DDR3 1333MHz
• 125W TDP
• 3GHz
• 4X (64kb+64kb) L1 cache
• 4x 512KB L2 cache
• 6MB L3 Shared Cache
• Dual Channel DDR2 800/1067MHz supported
• Dual Channel DDR3 133MHz
• HyperTransport bus frequency 3.6GHz
• Northbridge frequency 1.8GHz
• C1E
• Cool'n'Quiet 3.0
• True Quad Core x86 processor
• AMD64 with Direct Connect Architecture
• AMD Balanced Smart Cache
• AMD Wide Floating Point Accelerator
• Integrated DRAM Controller with AMD Memory Optimizer technology

CPU front

CPU rear

The Phenom II X4 is AMD's first 45nm CPU coming a full year after Intel's release on that process. In the past AMD made their CPUs at their FAB 36/38 facility in Dresden Germany. Earlier this month they spun off their manufacturing into GlobalFoundries which now manufactures their CPUs at the same facilities but under a different company name. The CPU is a 758 million transistor CPU compared to the 450 million found on the original Phenom X4 CPUs.

In terms of cache, the Phenom II X4 CPUs have the usual 64KB of data+64KB of instruction L1 cache that has been found on all AMD CPUs for the last few years. With four cores, the Phenom II X4 940 has 4x 512KB or 2MB total of L2 cache with each core having its own L2 cache. Note that AMD puts all of their processor cores on one package instead of the two cores per package that Intel has. This pays off with a single 6MB L3 cache which is shared between the cores.

AMD has been using the HyperTransport Protocol since the early Athlon days. HyperTransport provides increased bandwidth compared to the Front Side Bus that was used before hand. The Phenom II X4 has a HT link that operates at 3.6GHz, which when combined with the DDR2-1067Mhz memory bandwidth of 8.5GB/second, gives a total processor to system bandwidth of 37.2GB/second. That is more bandwidth than any other processor bus.

AM2+ 940+ AM3 710 front

AM2+ 940+ AM3 710 rear

Phenom IIs are the first AMD CPU core to support DDR3 memory, which replaces the DDR2 memory being used for system memory. To go along with the new memory controller is a new interface, Socket AM3+. The main difference between the two interfaces is the removal of two pins from the AM2+ Socket. This allows the AM3 CPUs to install onto a Socket AM2+ motherboard but not the reverse as there are two pins missing. Note that the Phenom II X4 940 is AM2+ and does not support DDR3 memory nor will it work on AM3 motherboards.

The Phenom II processors are designed to offer the same power requirements as the Phenom with the Phenom II 940 requiring a TDP of 125W. The move to 45nm does reduce the power draw as a processor with nearly twice the transistors requires the same power as its 65nm predecessor. The Socket AM3 CPUs that have recently been released require 95W, the same TDP as Intel's Core i7 CPUs. Also note that the AM3 CPUs will be clocked lower initially than the Phenom II X4 940. Here's a chart of the current AMD Phenom II lineup including AM2+ and AM3:

You'll notice that the Phenom II family is scheduled to have 8 models but only 4 have been released so far. Pricing on CPUs is always fluid with pricing going up and down according to demand. The prices I listed are the currently available prices on websites like Newegg and others linked to off AMD's website. One interesting note is that though the AM3 is AMD's newest platform, the highest speed CPUs are on the AM2+ platform. I'm sure that once product reaches store shelves we'll see the 925 and 910 CPUs available.