The Core i5-661 and Core i3-540 put to the test
Intel supplied us with a motherboard based on the H55 Express chipset and a Core i5-661 processor. In spite of our many requests, only this processor was available for testing. This is, to say the least, strange given that the range is so big.
Supplying the press with a processor with a spec that stands out from the rest with an IGP overclocked in comparison to the rest of the range isn’t without its own rationale and it’s obvious Intel wants to show this IGP off in the best possible light, ensuring it be tested at a clock of 900 MHz.
We were however able to get hold of a Core i3-540 for a few hours from another source – this only allowed us the time to test it in terms of pure processor performance. We were able to simulate Core i3-530 performance from these results by modifying the multiplier in the bios but it wasn’t possible to simulate the performance of other Core i5s from the 661 as Turbo modes differ from one processor to another and can’t be reset.
The use of a Clarkdale processor on the P55 Express motherboard requires an update to the bios. The system does work without this but not necessarily at optimum levels. While we didn’t have any problems with the Gigabyte P55A-UD4 and ASUSTeK P7P55D-EVO motherboards, on the Intel DP55KG the PCI-Express controller didn’t work as desired, even with the most recent beta bios, so much so that our graphics card was configured as PCI-Express x1, with the second PCI-Express port not functioning. An Intel motherboard that doesn’t support an Intel processor properly!
Energy consumption
Readings were taken at the wall socket, with the power supply yield at around 80%. For the test in load we used Prime95. This means that other components such as the graphics card or the hard drive are in idle when these readings are taken.
In idle the Clarkdales allow for even better energy consumption stats on the LGA1156 platform, which was already the best. In load, we’re at the same level as an LGA775 configuration with an entry level processor engraved at 45nm. All good here then!
Overclocking
We were able to overclock the Core i5-661 and it proved pretty much at ease when we did, reaching 3.8 GHz at 1.2V, 4 GHz at 1.25V and 4.2 GHz at 1.3V. We weren’t able to stabilise it at 4.4 GHz, even at 1.35V. Careful here, as while Intel advised users not to go over 1.55V at 45nm, after which the processor could be dammaged, at this engraving the limit is 1.4V!
