Core i7 4790K OC at 4600 MHz 1.3 Volts

The Next Chapter - Overclocking

Now we up the ante and boost 1.3 Volts into the processor. Understand that 1.3V and higher voltages are the levels where things get more challenging and could get into serious problems if you do not apply good enough cooling. We now set the Core i7 4790K @ 4600 MHz and apply 1.30 volts on the CPU while loading it with 100% stress for wPrime to run on all available CPU threads three times.

Core i7 4790K OC at 4600 MHz 1.3 Volts - IDLE 

Below, you can see the IDLE results with the Core i7 clocked at 4790K @ 4600 GHz with 1.30 volts on the CPU. Again, the results are the IDLE temperatures thus you are in your desktop doing pretty much nothing. 

Core i7 4790K OC at 4600 MHz 1.3 Volts LOAD

Now we'll be testing the temperatures under fully threaded stress. If we set the overclock at 4600 MHz and configure CPU Voltage at 1.3V, these are the results

The temps normally rise above and beyond 90 Degrees C for a lot of heat-pipe based coolers, which is a definitive no-no. As you can see, we have dangerous temperatures for most coolers.

LCS class coolers do better here and the H5 SF might be struggling, but for short bursts overclocked like this I am comfortable as to what I am seeing. You could however give the fan a higher RPM level, which probably will shave off a couple of degrees. But at the cost of much more noise. The reality is that very few coolers and kits can actually manage a Core i7 4970K @ 1.3+ Volts / 4600+ MHz temperature wise well enough.

So these are pretty nice results considering we are on a compact Mini-ITX platform.

Extended Tweaking

Since this solution harbors cooling capacity I extended overclocking to higher voltages relative to temperature and DBG levels as well.

The above numbers are just for reference only e.g. how does a 4790K behave with increased voltages at a 4600 MHz clock frequency. We can run the unit towards 1.45 Volts on the processor (which is an awful lot for this CPU!).

At this stage the system still boots and can finish two wPrime stress runs. Typically at 1.30~1.35 Volts and a good enough processor, you are in the 4.8 GHz range (if your CPU is capable). After 1.35 Volts the fans will start to spin faster though. You may consider up-to 41 DBa a normal airflow level, anything after that becomes noisy. At 1.45 Volts in the CPU the processor starts to overheat and gets loud (which is am irrelevant ridiculous voltage for this setup anyway). But yes, with this cooling solution we'd recommend 1.3 Volts max on a Core i7 4790K processor.