The Core i5 661 performed close to the Phenom II X4 945 when testing with Microsoft Excel 2007. The Core i5 661 was fastest dual-core processor tested, taking 39% less time to complete the MonteCarlo test than the Core 2 Duo E7400, and 44% less time than the Phenom II X2 550. It stood no chance against the quad-core Core i5 750 which was about 90% faster.

This time we are using WinRAR to carry out our own custom compression test using a single 4.5GB file and the Windows 7 DVD. Again the Core i5 661 delivers our best dual-core results and actually manages to match the Core 2 Quad Q6600 in terms of performance.

Adobe Photoshop CS4 doesn't appear to be well optimized for multi-core processors, at least not quad-cores anyway. This is made evident in our Extrude and Smart Blur tests, where we apply these filters to a high resolution image. The Core i5 661 is the fastest tested processor thanks to its 3.33GHz clock speed, allowing it to edge out the Core i5 750.