Power Consumption and Overclocking
I tested power consumption at the wall, so it takes into account the video card, hard drive, DVD drive, and another other add-in board plus the motherboard. I was able to get the idle power from both of the Phenoms, but due to how I had to downclock the Q9770 to Q9550 speeds, getting an accurate idle speed is impossible. Load numbers were taken while running the multi-thread portion of Cinebench.
The Phenom II, while running 400 MHz faster than the 9950, did not show all that great of a difference at idle. At load the Phenom II was actually more efficient than the much slower clocked 9950, and surprisingly enough was significantly lower in power consumption than the slower clocked Q9550. AMD has certainly made some big power improvements, and the best news is that they are still optimizing the Phenom II on the new 45 nm process. Six months from now we likely will see 95 watt TDP Phenom IIs running at 3 GHz, but the question is if AMD is going to get into another MHz race with Intel. There eventually will be a 3.2 GHz Phenom II, but roadmaps do not show that jump in clockspeed until Fall of this year.
Overclocking
This is one area that AMD has been quite proud of with the Phenom II. As evidenced by their special event last month, they are excited about the overclocking potential of these new parts and what it could mean to them possibly re-invigorating their enthusiast fanbase.
There are two overriding aspects towards achieving high clock speeds. The first is obviously the transistor switching speed with the associated process. The second is the actual design of the processor itself. For example, the Pentium 4 was designed to run at high clockspeeds, even on the larger 90 nm process. Hitting 3.8 GHz was the final leap for the Pentium 4, while the original Centrino on that same process was hitting a max of 2 GHz (if memory serves). The original Barcelona core was able to run at a max of 2.6 GHz with a final TDP of 125 watts on a highly optimized 65 nm process. We would often see overclocks in the 3 GHz range, and up to 3.4 GHz with extreme cooling and the use of ACC. It was a decent balance of IPC, clockspeed, and TDP on what is essentially a mature process.
The Phenom II is an entirely different animal. First off AMD’s 45 nm process appears to be very mature and has excellent power and switching performance right out of the gate. AMD also designed the Phenom II in such a way that not only did they improve IPC, they have allowed the design to achieve unheard of clockspeeds for an AMD based product.
My results did not reach the 6 GHz heights that AMD showed off last month, but considering how poor of an overclocker I am, my results are quite respectable for air cooling and a minimal amount of effort. Using stock voltage I was able to take the Phenom II X4 940 to 3.5 GHz on air cooling. My final overclock was at 3.8 GHz with a voltage of 1.45v. This is pretty close to the 4 GHz mark that AMD says is quite achievable with a good portion of their parts on air cooling. Again, I am not the world’s greatest overclocker and I am not a big fan of frying processors. 3.8 GHz with minimal effort is a nice accomplishment, and certainly the 3.5 GHz mark at stock voltage is probably the real winner here.
