Vital Signs and Overclocking
As you saw on the previous page, the new Socket AM3 Phenom II X4 and X3 processors look just like the original Phenoms, or older Athlons for that matter, due to the similar packaging and heat spreader designs. There are some subtle differences with Socket AM3 processors, however, that we should point out.
Socket AM3 processors are architected to work with both DDR2 and DDR3 memory, and with Socket AM3 or AM2+ motherboards. Socket AM2+ processors do not have this ability though, so AMD made some changes to the Socket AM3 pin configuration to prevent AM2+ processors from being plugged into the socket. Socket AM3 processors have 938 pins, whereas socket AM2 processors have 940, hence two pins have been removed from these new Phenom II processors. If you look close at the shot above, you'll notice that there are two groups of three and two groups of two pins removed on the underside of the AM3 processors--on AM2+ processors, four groups of two pins are removed. Keying the processors and sockets this way prevents AM2+ processors from being installed on AM3 motherboards, but allows AM3 processors to be installed on either type of motherboard.
The new Phenom II X3 720 Black Edition and X4 810 are both compatible with DDR2 and DDR3 memory, and support a 2GHz memory controller frequency. If you remember, the first Phenom II processors we showed you last month supported only a 1.8GHz memory controller frequency. TDPs are rated for only 95W and each CPU has a total of 512K of L1 cache, 2MB or 1.5MB of L2 cache (512MB per core), and 4MB or 6MB of shared L3 cache. The X3 720 Black Edition has a full 6MB L3 like earlier Phenom IIs, while the X4 810, and other 800 series Phenom IIs, will have only 4MB of L3.
To get a closer look into each processor's inner workings, we fired up CPU-Z to take a peek at thier core and cache configurations. CPU-Z correctly identifies the processors as Phenom IIs, based on the core codenamed "Deneb". As the information shows, the chips are manufactured using AMD's 45nm process technology and our particular samples have a stepping designation of 2 and core revision of RB-C2. The Phenom II X3 720 chip is clocked at 2.8GHz, due to its 14x multiplier and 200MHz base clock, the HT link is running at 2.0GHz, and there is 512K of L1 Data / Instruction cache, 1.5MB of L2 cache (512K per core), and 6MB of shared L3 cache available. The Phenom II X4 810 chip is clocked at 2.6GHz (13 x 200MHz) also with an HT link running at 2.0GHz and 512K of L1 Data / Instruction cache, but with 2MB of L2 cache (512K per core), and only 4MB of shared L3 cache.
Overlcocking with AMD's Phenom II processors has been interesting to say the least. By now, you all should know about the significant headroom left in these CPUs. So with that in mind, we set out to overclock them both using a stock AMD PIB cooler and MSI 790GX based motherboard. With only a bump in CPU core voltage to 1.5v, we were able to take the Phenom II X3 720 Black Edition to 3.6GHz with complete stability. Remember, Black Edition processors are unlocked, so we were able to achieve this overclock by merely altering the CPU multiplier in the system BIOS. The Phenon II X4 810 is not a Black Edition processor, so overclocking it required altering of the base HT clock frequency.
Our motherboard wasn't being very cooperative for this test, but with minimal effort we were still able to hit over 3.3GHz. With some better cooling and more aggressive voltage tweaking, we suspect even higher clock speeds than these will be possible. This is important to note because these processors are relatively inexpensive and should be attractive to you budget minded overclockers out there.