Voltage and Temperature Scaling
For this test, we set the vCore at 1.4v, apply 100 percent load, and record the maximum temperature at different frequencies. This test tells us how each CPU handles the same voltage and frequency settings; you can notice that 4790K A constantly maintains the lowest temperatures while performing the best in the other tests.
Interestingly enough, the CPU with the lowest stock VID has the highest temperatures by a substantial margin. Stability is not an issue for this test, and it's performed fast. All of our CPUs were able to maintain full load at 4.8GHz for a short period of time.
For this test, we lock the CPU frequency at 4.5GHz, and we turn the knob on the vCore from 1.2v to 1.5v while keeping every other setting constant. This test reinforces the results from the previous test.
To be honest, overclocking the original 4770K on air was a bit disappointing when compared to previous Sandy Bridge processors. Even maintaining a stable 4.5GHz overclock was challenging for some. However, it is quite easy to see that the new Devil's Canyon 4790K brings great improvements in that regard, even comparable to Sandy Bridge overclocks, but with the performance that comes with the 22nm Haswell node.
The temperatures seen with these CPUs would have been unheard of with the 4770K, unless you were daring enough to de-lid the CPU. With the improvements in temperature comes the ability to pump more voltage into the CPU core, and Intel seems to have anticipated this and nurtured it with a change in the capacitor allotment on the CPU. The two small changes in the TIM and capacitor allotment that Intel made have provided higher overclocking headroom, which is clearly apparent.
Interestingly enough, the stock VID doesn't correlate to maximum CPU speed like we are used to seeing. Perhaps this is because of the binning process and the need to sustain a 4.4 GHz overclock. Perhaps some CPUs exceeded their TDP threshold and required a lower stock VID to compensate and keep the CPU within the proper TDP limits. Either way, lower VID seemed to mean higher temperatures; at the same time, maximum clocks were not directly related to having a low VID. While our sample size of three CPUs is quite small to draw any conclusive results, it is enough to show us that the batch number really doesn't indicate much.
As Intel improves their yields, this should change, perhaps in time or with another stepping if Intel decides to make one. Overall, the 4790K overclocks pretty well. Our worst sample maxed out at 4.6GHz, and our best maxed at 4.85GHz. While this isn't a huge overclock over the base turbo, it's a very high speed to be operating at, especially compared to the 4770K. All of our CPUs were able to get to 5GHz, but with little stability. However, you can easily improve on this with better cooling. We would say that Intel has provided a viable replacement for the 4770K, one with more overclocking potential, which should make overclocking much more enjoyable for those of us who choose to partake.
PRICING: You can find the Intel i7-4790K for sale below. The prices listed are valid at the time of writing but can change at any time. Click the link to see the very latest pricing for the best deal.
United States: The Intel i7-4790K retails for $329.99 at Amazon.
Australia: The Intel i7-4790K retails for $470.99 AUD at Mighty Ape Australia.
New Zealand: The Intel i7-4790K retails for $499.99 NZD at Mighty Ape NZ.