Core i7 3820 processor review

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Overclocking the Core i7

 

Overclocking - the Core i7-3820 on MSI X79

The original Sandy Bridge processors at the default baseclock (BLCK) were rather horrible to overclock. It has a lot to do with how the processor deals with the embedded graphics subsystem. If you were lucky you'd be able to increase the baseclock maybe 5 to 10 MHz multiplied at best. This is why the K and now X model processors have been introduced, easy overclocking by increasing the multiplier up-to a multiplier of 57.

This feature of course remains the same for Sandy Bridge-E with the X (Extreme) and K models. However, you should be able to overclock on the baseclock a little better now as well thanks to a new buffer chip. increments.

With the 3820 processor being limited on the processor multiplier, you'll normally have to overclock based on the baseclock.

Manual overclocking
The true guru3d audience overclocks from the BIOS and try to find the maximum stable limit. The generic overclock procedure for multiplier based overclocking is as follows:

  1. Increase baseclock BClk speed towards 125 MHz
  2. If optional in the BIOS, increase your TDP limits of the processor to 250 Watts (by that you are allowing a higher power draw)
  3. Disable turbo mode
  4. Set your base multiplier at your preference e.g. 37
  5. Increase CPU voltage, though setting AUTO might work fine, we applied 1.5V on the processor cores
  6. Make sure your processor is properly cooled
  7. Save and Exit BIOS / EFI
     

Now typically by using this method you'd end up at 37x125=4625 MHz. We've seen 3820 processors even go over 5 Ghz using this method.

However for whatever reason our overclock would not kick in and the system would not post whatever we tried. This included a wide variety of memory settings, firmware updates and voltages as well.

In the end we gave up and decided to just overclock based on the maximum multiplier of 43, hence we overclock to 4300 MHz. So in short, you disable turbo mode, increase the MP to 43 with the BLCK at 100 MHz. And that did work flawlessly. The good thing is that we did not need extra voltage for this. And the bad thing, we really wanted to be a few hundred MHz higher in the clock frequency.

Core i7 3820

Let's have a quick look at a Prime95 stress test with all four cores active and stressed at 4300 MHz. As you can see, you'll need a reasonable cooler, temperatures are acceptable thanks to the fact we did not use voltage tweaking on the processor.

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