The width of a bandThe Phenom family of processors has evolved far past the original AM2+ socket. It now resides within the AM3 socket, but the socket may still be limited somewhat by bandwidth designed for fewer cores. While it is certainly fast at stock speeds of 3.2GHz at 200x16, will it get enough data to the processing cores when overclocked? To see if this was actually a problem we boosted the HyperTransport bus to 267x12, amping up the platform's speed while maintaining the processor's operating frequency at 3.2GHz.
With the frequencies locked at 3.2GHz, the faster platform speed resulted in a slight performance increase across the board, though it only granted an extra two per cent. We ran the same tests at an increased memory speed of 1780MHz, but this still only gathered a three per cent improvement. To that end, the bandwidth of the socket isn't going to hinder the performance of the X6, though increasing platform frequencies will net marginally higher speeds at the same processor speed.
Instead, we noticed the most significant performance boost when overclocking the X6 the traditional way - raising the HT bus steadily until we reached a maximum ceiling of 268x16 for a final clock speed of 4288MHz, a 34 per cent overclock. This required an aftermarket heatsink with three 120mm fans - it ran far too hot to be practical for everyday use - but did return Cinebench scores of 24729. Impressively, this represented a 36.6 per cent performance increase; when factoring in the platform speed increase and processor frequency, it's a linear increase in actual performance, too. We'd expect performance to continue increasing as processor frequency continues, and the X6 would be a perfect candidate for LN2 cooling.
It ain't over till...AMD has lovingly crafted its master work; the one chip that they're hoping will turn the audience's affections their way, ensuring many tickets - and chips - are sold. While it isn't a major processing architectural change, six cores are effectively 'glued' together for a price well over a thousand dollars cheaper than Intel's offering, and while the single-threaded performance sits slightly lower than the i7 870, multi-threaded performance is significantly higher - giving even the i7 965 a run for its money. More surprisingly, even when the i7 870 is overclocked to 4246MHz it'sstill beaten by the overclocked X6!
For a processor boasting this many cores and a price just shy of $400, it's a stunning sign that AMD still knows how to deliver a damn good performance - one that we're finally tempted to pay for.
Issue: 137 | June, 2012