When Intel released its 5300 series quad-core Intel Xeon processors earlier this month, we wondered how they would compare to their dual-core Intel Xeon 5160 predecessors. So, we pitted the two directly against each other, comparing our benchmark results of the dual-core 3GHz Intel Xeon 5160 HP xw8400 machine we reviewed earlier this month head-to-head against a similarly-prepared HP xw8400 workstation equipped with two of these new quad-core Intel Xeon X5355 processors running at 2.66 GHz which Intel is officially naming Core 2 Quad. Was there a big difference between the two?