We tested the processors using the Biostar TPower I45 we just looked at, as it happened to be on the test bench. You need to handle the figures with a modicum of care as we have been giving the WD 300GB VelociRaptor a work-out so the hard drive figures in PCMark05 are higher than you might expect. The other point worth mentioning is the issue of memory speed that came up in the Biostar review as the thing is incapable of running memory at a speed of 1,066MHz so we had to leave it on 800MHz.
Provided you take the figures in this review in isolation things will be fine but if you use either of these processors on your own P45 motherboard you’ll likely find you get better memory performance while your hard drive will be slower.
At idle the Q9300 system draws 20W less than the Q6600 and that’s despite the fact that we expected Intel’s SpeedStep power saving technology would have a greater effect on the Q6600 than the Q9300. In both cases SpeedStep drops the multiplier to 6x so the Q6600 slows from 9x266MHz=2.4GHz to 6x266MHz=1.6GHz while the Q9300 slows from 7.5x333MHz to 6x333MHz for a speed of 2GHz.
When the processors were working flat out in POV-Ray the Q9300 had an edge but it was almost entirely due to the extra 100MHz of clock speed and it was the same story in PCMark05. If you have no plans to overclock your processor then you’ll see no extra performance with a change from Kentsfield to Yorkfield but the difference in power consumption is startling as the faster Q9300 draws 40W less than the Q6600 when the systems run POV-Ray.
When it comes to overclocking the two processors behave quite differently. The Q9300 will run a front side bus of 430MHz which is almost exactly 100MHz more than the stock speed of 333MHz. The multiplier has to be dropped from 7.5x to 7x but we had no need to tinker with the Voltage settings for the chipset and processor. When we tried to push the front side bus to 450MHz we found that extra power made no difference and the speed remained stubbornly fixed at 3.01GHz.
It was a different story with the Q6600 which also tolerated a front side bus increase in the order of 100MHz. We raised it from 266MHz to 380MHz and left the multiplier at 9x for a clock speed of 3.42GHz. That’s an overclock of 1GHz for the Q6600 and 500MHz for the Q9300 however the performance of the Penryn was significantly faster than the Kentsfield. The other numbers that jump off the page are the power consumption figures which don’t change much for the Q9300. At idle it’s a mere 5W and under load the overclock only costs 25W or to put it another way the overclocked Q9300 draws less power than the standard Q6600.
With the overclocked Q6600 loaded to 100 percent with POV-Ray the system draws a shocking 310W which is a full 125W more than it drew at stock speed. You won’t be surprised to learn that we had to crank up the fan speed of the CPU cooler but it was relatively easy to keep the processor at a healthy 45 degrees Celsius. During PCMark05 the processor load was less extreme and the power draw was a ‘mere’ 260W.
In a straight choice between the Q9300 at 3.0GHz drawing 170W and the Q6600 at 3.4GHz drawing 310W we’d choose… well we don’t need to spell it out really do we?
The Q9300 may sound relatively expensive compared to the Q6600 but it’s well worth the extra money. Kentsfield is history and Penryn rules the heights.