|Preliminary Testing with SiSoft SANDRA 2009|
Sandra's CPU test shows the Core i5's integer performance winning past the slower-clocked i7's, despite the latter's use of HyperThreading. The tables turn in FPU code, where the assembled Core i7 processors are able to make better use of their virtual cores. Here, the Core i5 lags even the CyberPower system by 20 percent, despite its 35 percent higher clockspeed.
If you're wondering about the difference between the arithmetic and multimedia tests, it's laid out in Sandra's help file. Both benchmarks measure CPU performance, but the Dhrystone/Whetstone benchmarks measure a processor's raw capability to execute integer or floating point instructions. Sandra's multimedia suite is designed to test the various SIMD capabilities of a processor. In the company's own words: The test involves the generation of Mandelbrot Set fractals that are used to realistically describe and generate natural objects such as mountains or clouds. By using various multi-media extensions better performance is achieved.
HyperThreading makes a difference here, but you can also see where the 3.8GHz core cock on the i5-750 keeps that chip near the head of the pack.
The Core i5 is limited to "just" two memory channels, making its bottom-end showing in this particular benchmark a foregone conclusion. Note, however, that Lynnfield isn't missing that extra channel all that much, even in a theoretical test. The CyberPower and iBuyPower only lead the Digital Storm rig by about 20 percent—a significant gap, but not as large as one might expect based on raw bandwidth numbers. Don't expect the bandwidth difference to have much of an impact on our actual tests—consumer applications and games are typically more latency-sensitive, than bandwidth-sensitive.