Ever since AMD's tantalizing preview of an AMD Phenom II processor running at 6GHz hit the YouTube, it has been one of the more discussed aspects of the company's new CPU. How much better does it overclock compared to its predecessor, the Phenom X4?
By all accounts, the Phenom X4 was a failure when it came to the overclocking department. One would be hard pressed for it to reach 3GHz on air cooling and barely pass 4GHz even with liquid nitrogen. A quick search online showed that a clock speed of 4.2GHz was the highest documented record for the Phenom X4. And here was AMD showing a 6GHz Phenom II (liquid nitrogen) before it was officially launched.
So did AMD have a better chip up its sleeves? Well, as our review of the Phenom II showed, the sequel is undoubtedly the superior. Considering that the top model, the Phenom II X4 940 Black Edition started at 3.0GHz, a 400MHz boost over the Phenom X4 9950's 2.6GHz, one could probably conclude that AMD has managed to increase the clock speeds this time round. Hence, we decided to try our hand at overclocking our Phenom II X4 940 Black Edition with air cooling and find out first-hand what the average AMD enthusiast can coax out of it.
Our setup was exactly the same as our benchmarking setup for the Phenom II and is listed as follows:-
While one could juggle the various frequencies on the AMD platform to get the best outcome, we only concentrated on the multiplier since we had an unlocked Black Edition. This meant that we did not try to push the bus speed which remained at 200MHz. We did increase the HyperTransport and memory bus clocks up to 2.0GHz, similar to that on the Phenom X4 9950.
Without increasing the core voltage, the Phenom II X4 940 easily managed 3.4GHz. To push it higher, we started increasing the voltage and soon hit the 'unsafe' (and power hungry) levels of more than 1.5V. We could perhaps have pushed it further but unwilling to try our luck, settled at 3.8GHz. This was on air-cooling, with no other tweaks besides boosting the core voltage and the multiplier.
Obviously, this is still some way from the demonstrated 6GHz from AMD but then again, one can hit that only with liquid nitrogen cooling. Compared to the original Phenom, the new CPU definitely has much more headroom for overclocking. But does the higher clock speed help the Phenom II against Intel's quad-cores? We ran some benchmarks and the results are detailed after the jump.