More and more PCs are being sold pre-overclocked, and it's not hard to see why. Not only is it desirable to squeeze extra performance from your machine, but the job is now arguably easier. Cooling systems are more elaborate today, with cases featuring multiple fans to maintain a good airflow.

The latest processors also help, with the benefit of lower thermal envelopes than the previous generation.

An overclocked PC also has extra value on the shop shelf. The components are all specially chosen to deliver the best performance possible, tested and still under warranty, despite being pushed to speeds beyond what they were meant for.

Overclocking was once only the realm of hardware enthusiasts, but now giant IT companies such as Dell are selling overclocked high-end PCs. With a nod from such a big name, overclocked computers are going to be more than a passing trend.

The Infinity SLI 960 is a hardware enthusiast's dream. The Intel E6700 is running happily at 3.1GHz, enough power to push the two GeForce 8800 GTX cards as far as possible. This overclock from 2.66GHz is all the more impressive as it has been achieved with just standard air cooling.

Two hard drives in a RAID 0 stripe provide ample transfer rates to keep the CPU fed with data. With 2GB of DDR2 from OCZ in an Asus P5N32 SLI motherboard, one of the fastest around, there is almost nothing to complain about with this machine's specification.

Going with the flow

It's safe to assume that an overclocked PC will come armed with lots of fans, and Cyberpower doesn't disappoint. The processor fan is a monstrous Thermaltake Big Typhoon cooler, with a 120mm fan sitting atop a giant copper heatsink.

This blows air onto the four 120mm side fans which then push it outside the system. Three more 120mm case fans are installed in the front, back and side to improve airflow, in addition to an 80mm fan at the top and air vent at the bottom.

With all these fans blowing air, as well as those on the GPU and the two hard drives whirring away, this isn't the quietest PC around. However, the airflow is so good in the case that we disconnected the four fans on the side without any temperature problems, instantly reducing the decibel output.

The best aspect of the Infinity is the sub-£2,000 price tag, including a 22in screen. This makes the Infinity one of the best value high-end PCs we've seen. This is despite a few irks we have with it.

The demo unit we were sent came with Windows Vista Home Premium installed. For a high-end PC clearly aimed at the gamer, you have to wonder, why? Microsoft's flashy OS simply can't deliver the frame rates that the same hardware can with Windows XP.

Granted, with this power you won't find games are exactly slow under Vista, but the inefficient drivers negate some of the performance boost from the overclocked processor. Two GeForce 8800 GTX cards running in SLI suffer a major performance hit with Vista, to the point where the performance of two cards under Vista is only marginally better than a single card with XP.

The good news is, you can leave Vista off the list in Cyberpower's customisation options, and if you are a gamer, we suggest you do.

If you're looking for a PC for other tasks, then the Infinity SLI 960 wouldn't be a first choice. Much of the cost has gone on the graphics setup, the most important component to deliver high frame rates in 3D apps. A video editing workstation would get more benefit from a faster RAID array, using 10,000 RPM Western Digital Raptors rather than the Maxtor drives in the demo unit.

Likewise, a higher memory capacity than the standard 2GB would be a bonus for intensive design work. 4GB of memory or more means a lot of technical issues, including necessitating the use of a 64-bit OS. This has even less efficient drivers, and games rarely make use of more than 2GB of address space, even on a 64-bit platform.

Instead, Cyberpower uses fast OCZ DDR2 modules that help make the overclock possible, a wise compromise that results in a better gaming platform.

The Infinity SLI 960 is not the last word in high-end PCs, but it offers almost everything a gamer could want. The real icing on the cake is the price, an overclocked PC that won't leave you feeling ripped off.