Verdict: The Impression doesn't make a good impression

Impression is really a bad name for any product, since it raises your expectations so high they can't easily be satisfied. So either AOpen has so much confidence in its latest case that it reckons the Impression really is out of this world, or the company simply didn't think through the name properly.

The Impression is the smallest case in this Labs test - in fact, it has a depth of just 450mm, which makes it very difficult to build a PC inside. For example, there's barely any room to plug the PCI-E power connector into the back of your graphics card(s). The crossbar next to the PSU also restricts access to the motherboard, so realistically, you have to install the CPU, HSF and RAM in the motherboard before screwing it into the case.

Despite its small dimensions, the Impression has lots of drive bays: four 5.25in external, two 3.5in external and five 3.5in internal. Cool air is sucked in at the front by a 92mm blue LED fan, but as the front intake is just a small hole at the bottom of the front panel, air has to move through 90 degrees before entering the case. Unfortunately, because the 3.5in internal drive bay cage is mounted at a 90-degree angle to the front of the case, and has few perforations through which the air can pass, it restricts the flow of air into the motherboard chamber. So despite the 120mm rear exhaust fan, sufficient air simply isn't drawn through the case, and components become increasingly hotter, as shown in the infrared photograph. For example, despite the metal of the hard drive cage hovering at around 25ûC, the hard drive itself was a toasty 50ûC under load.

After approximately 40 minutes of running 3DMark06, the temperature inside the Impression seemed to have stabilised, although it was extremely high. The CPU had skyrocketed from 51ûC at idle to 82ûC, the Northbridge from 45ûC to 66ûC, the hard drive from 36ûC to 50ûC, and the GPUs from 68ûC to 110ûC. This means that the Impression cooled our test PC less than any other case in this Labs test. It compares very poorly with the best cooling cases, the Akasa Mirage and Antec P180, which, on average, cooled each component to 10ûC lower than the Impression. The CPU temperature is very disappointing, considering that the CPU air guide on the left side panel is supposed to vent cool air directly into the CPU HSF.

The infrared photograph also reveals how hot air is trapped at the top of the case, which heats up the PSU. Fortunately, we selected a Seasonic S12-600 PSU precisely because it's very efficient, and runs cool compared with most other PSUs, so it wasn't adversely affected by the high air temperature. A lesser PSU's outputs may drop or fail altogether, however.

Despite the side-mounted CPU air guide, the restrictive front intake and restrictive 3.5in drive cage means that air finds it very hard to pass through the Impression. As our testing proves, the Impression fails to keep components as cool as other cases, so it really can't be recommended for a high-end PC. The Oven would be a more appropriate name for this case.

• Cases - 21st November 2008
• Motherboards - 24th October 2008
• Gaming Headsets - 26th September 2008
• Dream PCs - 24th September 2008
• Headphones - 12th September 2008
• Media PC components - 22nd August 2008
• PSUs - 14th July 2008

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