|Intel Sandy Bridge Overclocking Guide|
|Articles - Featured Guides|
|Written by Servando Silva|
|Tuesday, 19 April 2011|
Page 7 of 10
Overclocking Frequency vs. VoltageFor all you readers who decided to jump the first pages and go straight to the results, I must repeat that there's no interest on testing performance's difference between non overclocked and overclocked setups. That point has been addressed in all our CPU/Motherboard/RAM reviews we've done in the past, and it's up to you to decide whether you need to overclock or not, and how much is "enough" for you. Getting to the point, in this first section I'll be showing how CPU frequency increases against CPU vCore. All those charts are the result of several hours trying and testing different settings and the results reported were 100% stable (considering the stability's paradigm explained before).
As you can see, both Sandy Bridge processors have a vCore around 1.1 volts. This is the reason Sandy Bridge achieves pretty good temps at load conditions at factory settings. The first step was bumping CPU frequency to 4GHz. For this, I just increased CPU multiplier to 40x and added a few milli-volts to the vCore. Both processors were able to achieve 4GHz with 1.15v, which is a very outstanding result. Let's keep in mind that Lynnfield and Nehalem processors needed more voltage (around 1.3v or more) to achieve 4GHz. The only processors able to reach 4GHz almost at stock voltage were the Core i3 and Core i5 Clarkdale CPUs, but all of them worked with 2 cores/4 threads.
With Sandy Bridge we're not going to break any record at 4GHz, so my next step was passing to 4.4GHz. I'd say this is the best frequency according to CPU temperature and power consumption. It required something around 1.25v to keep both processors rock stable. Up to this point, it seems both the Core i5 and the Core i7 require similar voltages to achieve the same frequencies. However, let's not forget that the i7 has 2MB of extra L3 cache and works with Hyper Threading technology.
Finally, I set my highest stable point at 4.8GH. I needed almost 1.4v for the Core i7 and 1.4v for the Core i5 in order to achieve a stable platform here. With those voltages, the CPUs reached the limit and the temperatures raised a lot against stock settings. Just for fun, I tried getting 5GHz stable without any success. I would need a better motherboard and probably a better heatsink with more than 1.45v in order to achieve my dream, but I didn't want to risk any of my CPUs just for a test.