PCMark05 likewise confirms the slight gain the 1333MHz FSB brings a boost of a mere percentage point to most tests except Memory, where those extra cycles give you a four per cent increase on PCMark scores. The FSB factor is also highlighted by our SiSoft Sandra readings.

Incidentally, we put the difference in PCMark05 CPU scores between the E6700 and E6750 down to the inherent errors in PCMark05's readings - had we run the benchmarks more time, these errors would be averaged out and we'd get CPU scores for each processor that are near enough identical.

SiSoft Sandra memory results

Bandwidths in MBps
Longer bars are better

Latencies in ns
Shorter bars are better

When we were testing the E6750 we got the impression that it was throwing off noticeably less heat through the CPU coolerthan the E6700 was. We were using a Zalman CNPS8000 cooler with the fan turned down to a reasonably low speed to keep the noise down.

We decided to investigate further by running Intel's Thermal Analysis Tool. The software monitors the temperature of both cores on a dual-core processor and has the facility to drive the cores at full load. Unfortunately it gets confused by a quad-core CPU so you can't compare the figures for the QX6800 and QX6850 with the E6700 and the E6750 but even so they make for interesting reading.

Intel Thermal Analysis Tool results

Temperatures in °C

Related reviews

• Intel 'Penryn' Core 2 Extreme QX9650
• Abit IP35 Pro Intel P35-based motherboard
• Asus Maximus Formula Intel X38-based mobo
• Nvidia GeForce 7150/nForce 630i integrated chipset
• Alienware Area-51 m9750
• Intel Core 2 Extreme QX6850 & MSI P35 Diamond mobo
• Intel power PC platforms: Core 2 Extreme QX6800 and V8
• Hitachi Deskstar 7K1000 hard drive
• EVGA 680i LT SLI nForce-based motherboard
• AMD 690G integrated chipset
• Intel Core 2 Quad Q6600 four-core CPU
• Intel Core 2 Extreme QX6700 quad-core CPU

When idle, the E6750 runs 26°C cooler than the E6700 and is 19°C cooler under full load. Those figures are clearly being read from the thermal diode in the processor core so you won't see a 20°C drop in the heatsink temperature, but there is a very noticeable difference in air temperature which is, of course, the reason we ran this check in the first place.

Verdict

The combination of reduced price, increased performance and lower heat output makes the Core 2 Duo E6750 a compelling buy. For the time being we're not sold on the P35 chipset or DDR 3 system memory, but that's fine as we're biding our time and waiting patiently for X38.