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AnandTech: Intel Core 2 Duo E6750 Preview: The Desktop Gets a 1333MHz FSB
X-bit labs - New Member In Core 2 Duo Processor Family: Introducing CPUs with 1333MHz Bus (page 11)
Intel's Core 2 Duo E6750 processor - The Tech Report - Page 14Overall, the 1333MHz FSB doesn't do much for dual core processors. Over the 20 benchmarks we sampled for this chart, the 1333MHz FSB gave us an average improvement of 1.9% over the 1066MHz FSB. There are two unique outliers in the chart: Oblivion with a 6.1% improvement and Photoshop CS3 with an 11.2% increase in performance ... The clock speeds Intel is launching its 1333MHz FSB processors are basically the same ones that Intel first introduced the Core 2 at; we weren't FSB bottlenecked back then, thus there's no reason to expect a huge increase in performance by bumping the FSB today ... As Intel ramps up clock speed and continues its transition to quad-core the 1333MHz FSB will be more important, but today it's by no means a necessary feature. There's a bigger performance impact from having more L2 cache (e.g. 4MB vs. 2MB) than from the 1333MHz FSB, which is great news for present day Core 2 owners.
Our Core 2 Duo E6750 sample was a particularly great overclocker, at stock voltage with a retail Intel heatsink/fan we were able to run the system at 3.68GHz (460 x 8.0):
With further voltage tweaking slightly faster speeds should be possible, but at default voltage we were quite impressed. Whether or not this is a testament to the maturity of Intel's 65nm process has yet to be seen, but this next batch of Core 2 processors that will be appearing in the summer could be great overclockers. It's not a tremendous surprise given that Intel's 65nm process should be quite mature at this point, as Intel is on the cusp of introducing its first 45nm processors.
After an epic, trial-and-error iterative process, I finally decided that the max stable clock speed for this E6750 is 3.64GHz, nearly a full gigahertz higher than stock. That's with a core voltage of 1.3875V and nothing fancier than regular old air cooling ... That's a heckuva nice overclock from a relatively high speed grade CPU, and happily, its higher base FSB speed didn't get in the way; we still had a little bit of room left before hitting the motherboard's apparent bus speed ceiling ... At this speed, the E6750 is the fastest dual-core processor we've ever seen.
X-bit labs - New Member In Core 2 Duo Processor Family: Introducing CPUs with 1333MHz Bus (page 11)
Intel Core 2 Duo E6750 Performance Preview - HotHardwareThe first one to get to the testbed was Core 2 Duo E6850 processor. By raising its Vcore to 1.5V we managed to get it to work at 3.79GHz (9 x 420MHz) without any stability issues.
The second overclocking experiment was devoted to Core 2 Duo E6750 with the nominal frequency of 2.66GHz and 8x default clock multiplier. The maximum FSB frequency we managed to achieve for this processor by raising its Vcore to 1.5V was 461MHz. So, the tested Core 2 Duo E6750 hit 3.69GHz.
The third CPU, Core 2 Duo E6550 ... We managed to overclock our processor to the maximum of 3.57GHz with the Vcore increased to 1.5V. To hit this frequency we raised the FSB to 510MHz thus getting a 53% frequency increase above the nominal. Note that in this case we didn’t hit the FSB Wall but simply exhausted the processor capabilities.
So, new Core 2 Duo processors with 1333MHz bus overclock pretty well. The new G0 core stepping obviously proved up to the mark here.
By bumping the processor's core voltage to 1.45v and increasing the front side bus speed via our Asus P5K Deluxe motherboard's BIOS, we were able to take the Core 2 Duo E6750 up from its default clock speed of 2.6GHz to an impressive 3.92GHz (multiplier=8x / Front Side Bus Frequency=490MHz. This was done using the stock Intel CPU cooler on an open-air test bench. At that speed, the CPU completed a Cinebench rendering pass in just 18 seconds and it blew past the Core 2 Extreme X6800 in SANDRA's Processor Arithmetic benchmark.
We should also note that throughout all of our overclocking experiments, the CPU barely hit 48°C and it seemed to heat up and cool down very quickly. We've only spent a limited amount of time with this chip and haven't experimented with multiple motherboards just yet, so we're not certain these temperature readings are accurate, but this early data suggests that this new revision of Conroe runs quite cool and has excellent overclocking potential.