The Phenom 9600
Physically and besides its label, nothing distinguishes a Phenom from a classic Socket AM2 processor. You may recall, the Phenom and all AM2+ processors are
supposed to function on all existing AM2 motherboards. This is something that hasn’t necessarily been verified in practice as we show later on in this article. In this case, the HyperTransport bus which functions at 1.8 GHz on the AM2+ is retrograded to 1 GHz and the frequency of the memory controller is also decreased as the AM2 does not allow managing the power of cores and memory controller separately.
The Gigabyte GA-MA790FX-DQ6
The Phenom tests were carried out on a motherboard based on the latest AMD chipset, the 790FX. Developed by Gigabyte, the GA-MA790FX-DQ6 has no less than 4 PCI Express x16 ports and in addition to functions inherent to the chipset, integrates two Gigabit Ethernet PCI Express Realteak ports, a controller enabling the support of two supplementary SATA, and a FireWire chip.
Power consumption
We measure power consumption of the processor’s power supply stage with the help of an ammetric clip on the ATX12V connection line which it uses exclusively. This allows us to better isolate CPU power use instead of obtaining overall consumption. The only thing we should keep in mind is that the CPU power supply stage has an efficiency of between 80 and 90%.
Note that Cool’n’Quiet could not be activated on the motherboard whether it was for the A64 or Phenom. Also, we couldn’t include the QX9650’s power consumption measurements with 1 or 2 sessions of Prime 95 because we no longer had the CPU at the time of this test.
As you can see, the Phenom 9600 consumes as much as an Athlon 64 X2 6400+ in load as well as in stand-by. Compared to an Athlon 64 X2 4400+, it’s almost double. While the QX6850 is above a Phenom in terms of power use, the QX9650 is below thanks to its 45nm while at the same time offering an entirely different level of performance.
Overclocking
Even if AMD has not set the Phenom above 2.3 GHz at this time, curiosity led us test the overclocking limits of the 9600. We were able to adjust the processor from 11.5x200 to 11.5x225 MHz or 2.58 GHz with a voltage of 1.25V. 2.64 GHz was reached with a voltage of 1.3V and these results were validated with 4 sessions of Prime95 for 15 minutes.
AM2 (in)compatibility ?
Due to a lack of time, we were only able to test AM2 compatibility with one motherboard, the M2N32-SLI Deluxe from ASUSTeK. Unfortunately, once the Phenom was installed the system did not boot and the motherboard shut down after several seconds. Installation of the latest bios beta 1402 dating from the end of October didn’t change things. Here is something to monitor and we hope that a bios update will add this much awaited retro-compatibility.
Cache speed
Tests carried out with RightMark Memory Analyser show a significant improvement of cache management with the Phenom compared to the Athlon 64 X2 65nm. The L1, L2 and L3 caches display respective latencies of 3, 9 and 20 cycles versus 3 and 22 for the L1 and L2 caches of the Athlon 64.
Bandwidth was also improved because L1 is almost four times as fast in reading and twice as fast in writing. L2 is 2.5 times faster in reading and 1.6 times faster in writing.
The tests
There was really only one real problem encountered in tests : with the Phenom it was impossible to stabilize the Spider platform with a memory controller Command Rate at 1T despite attempts with various 2x1 GB memory kits. On the motherboard’s original Gigabyte bios, adjustment caused instability while with the latest bios the Command Rate remained at 2T despite what the bios indicated! Not a very elegant solution to sidestep this problem...
Here is the rest of the test configuration:
We now move onto a comparison of these processors with other dual and quad cores in our usual test suite. Here is our test configuration:
- GeForce 8800 GTX / ForceWare 169.01
- 2 x 1024 MB DDR2-800 4-4-4
- 2 x Raptor 74 GB
- Windows XP SP2 French
- Socket 775 : ASUSTeK P5K Deluxe
- Socket AM2 : ASUSTeK M2N32-SLI Deluxe (A64 X2 6400+)
- Socket AM2+ : Gigabyte GA-MA790FX-DQ6 (A64 X2 4400+ & Phenom)
In addition to the Phenom 9600 in its standard configuration, we also tested it with the activation of only 2 and then 3 cores. With 2 cores we can better see performance improvements related to architectural modifications.
