PC Mark's system test shows a surprisingly small lead for the high-speed Core 2 Extreme QX9770. Is it even optimized for quad-core processing?
A look at PC Mark 2005's CPU test proves that the benchmark does use all the cores, even if it doesn't use them "well".
PC Mark's memory test score shows an increase in bandwidth for four-core processors, with the QX6850 beating the Core 2 Duo E6750 at a common stock bus speed. Overclocking the QX9770's four cores allow its moderate bus speeds to approach the memory access of the E6750's more highly-overclocked FSB.
SiSoft Sandra's CPU Arithmetic benchmark knows how to take full advantage off every core, and the QX9770 gains from its combination of core technology and clock speed.