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Before finally moving on to the benchmarking phase there are a few more important things we need to look at. Given that we are only using the standard Intel box cooler that comes with the E4600, it is important to check the operating temperatures when under load.  The above image gives us a similar read out to what CPUz would for example. Now because the EIST (Enhanced Intel SpeedStep Technology) is enabled you will notice that rather than 3.0GHz, Everest is reporting that the CPU speed is just 1.50GHz using just 1.188 volts. This power saving technology has wound back the processor because its power is not being called into play at this particular point in time. This feature can be disabled if you wish, but it does not have an effect on the overclock.   The above screen shots taken of CPUz show EIST in action! When the power of the CPU is not required the multiplier is dropped down to just 6x which effectively halves the CPU’s operating frequency from 3.0GHz to 1.5GHz, and in the process reduces the voltage from 1.264v to just 1.160v, which is a dramatic saving.   The next two screen shots are taken in Everest and they show the various operating temperatures of the CPU and motherboard when at idle and also under load. Note the increase in fan speed from 1875-RPM to just 2123-RPM when under load. When operating at 1.50GHz the E4600 coasts along at room temperature, being 24 degrees as reported by each core. The motherboard also operates at a relatively cool 33 degrees. Then when we fully load up the processor and it kicks into gear at 3.0GHz, the core temperatures rise to 48/51 degrees, while the motherboard is now at 37 degrees.     At 3.0GHz the E4600 runs relatively cool tipping the scales at just 48/51 degrees using the standard Intel box cooler which is well within safety limits. Going to 3.30GHz required a bit more effort and more voltage. This increased the operating temperature when under load from 48/51 degrees to 65/66 degrees. This is almost a 30% gain in thermal output for a 10% gain in clock frequency, therefore the E4600 is most efficient at 3.0GHz!  The best way to determine if an overclock is stable is to run a program like Prime95 that loads up all cores creating 100% CPU utilization to generate maximum stress and heat. Prime95 also uses quite a lot of memory and will also help to determine if the memory is stable at a given frequency. When clocked at 3.30GHz, despite operating at significantly hotter temperatures, the E4600 was stable as shown in the above image. However, going to 3.40GHz would cause Prime95 to stop and no amount of voltage seemed to change this. Out of interest we tried using water-cooling to see if the E4600 would go further, but it seemed that 3.30GHz was about the limit of our E4600 processor. |
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