Verdict: Fancy a dual-core 3.6GHz-capable CPU for £90?
While both Intel and AMD would like us to all buy chips from their ridiculously overpriced Extreme Edition and FX ranges, the chances of that happening are less than those of Tony Blair stepping aside in favour of Ali G as Prime Minister.
However, as high-end and entry-level CPUs are made on the same production line, it's sometimes possible to get a bargain by buying a high-end CPU that's labelled and sold as an entry-level model.
A few months ago, you might have been lucky enough to pick up a Socket 939 Opteron 1-series, before AMD wised up to the fact that enthusiasts were buying Opteron 144 and 146s instead of more expensive Athlon 64s, and jacked up the prices. This month, another bargaintastic opportunity has reared its head: the Pentium D 805.
Most Intel CPUs suffer from the generally unfair reputation of being more expensive than their AMD equivalents. This is something of which the Pentium D 805 definitely can't be accused; at just a few pennies over £90 inc VAT, the Pentium D 805 is less than half the price of AMD's cheapest dual-core CPU, the Athlon 64 3800+, which typically retails for over £200.
So what game is Intel playing? The Pentium D 805 is, in every sense, a fully-fledged dual-core CPU with two physical cores. It's built on the same 90nm manufacturing process as that of other members of the Pentium D 8-series, so it supports SSE3, EM64T, EIST and Execute Disable Bit. However, while the 2.8GHz Pentium D 820 and higher models have a 200MHz FSB (800MHz effective), the Pentium D 805 is clocked at 2.66GHz and has a 133MHz FSB (533MHz effective). This is almost certainly because the Pentium D 805 was originally intended to be a 2.8GHz Pentium D 820, but failed to run 100 per cent stably with a 200MHz FSB (800MHz effective).
At 2.66GHz, the Pentium D 805 isn't a great performer, although, like all CPUs based on the NetBurst architecture, it's very fast when it comes to media encoding. Typically, it's about 6 per cent slower than a Pentium D 820, yet it's £74 cheaper. However, like the Socket 939 Opteron 1-series, the Pentium D 805 has bags of overclocking potential. Installed in an Intel 955X chipset-based Asus P5WD2 Premium motherboard, we raised the FSB from 133MHz (533MHz effective) to 180MHz (720MHz effective), which boosted the CPU frequency from 2.66GHz to 3.6GHz. Not surprisingly, this huge overclock provided a massive performance boost, raising the overall Media Benchmark score by nearly 31 per cent. The overclock also helped to boost the average frame rate in our CPU-intensive Rome: Total War game benchmark by nearly 30 per cent. Even better, we only had to raise the vcore from 1.3V to 1.4V to make this overclock stable. You'll still need a good HSF though, such as the Arctic Cooling Freezer 7 Pro.
We tried overclocking the Pentium D 805 further, and although it POSTed at 4GHz with a 200MHz FSB (800MHz effective), it wouldn't load Windows. At 3.8GHz, with a 190MHz FSB (760MHz effective), it ran some applications for a few minutes, but became unstable after five minutes or so. However, an air-cooled 940MHz overclock is still impressive, and it's possible mainly because the Pentium D 805 has such a high clock multiplier (20x).
CONCLUSION
Like the Socket 939 Opteron 144 and 146, the out-of-the-box performance of the Pentium D 805 leaves a lot to be desired, but all three of these CPUs are very overclockable. However, this is where the comparison ends, as the Pentium D 805 is a dual-core CPU, so it's potentially faster than any single-core Opteron 1-series CPU if you use dual-core optimised applications. The massive overclocking potential of the Pentium D 805 makes the much more expensive Pentium D-series CPUs and Athlon 64 X2 3800+ look expensive too. A dual-core CPU for under £90: how many enthusiasts thought Intel would do that before AMD?
