The CPUs, What To Look For

A few specific things stand out when it comes time to look at the CPUs themselves, and which one to buy, even before you get your hands on one. First of all, there are two fully "unlocked" chips right now, the Core i5-4670K and Core i7-4770K. The i5 chip is a quad-core without Hyper-Threading, while the i7 includes Hyper-Threading. If silicon quality is the same, the i7 is more likely to produce more heat because of its pseudo cores. With heat proving to be a big factor in how you overclock, this might be the first time I recommend users consider the Core i5-4670K for a long-term overclock. The Core i7-4770K should be just as capable, but I cannot state how huge heat issues can be enough.

Speaking of heat and chips, Intel stated that these chips are more than happy to run near the throttle point, and that temperatures might not play a large role in chip degradation, but since the chip itself is larger, with greater functionality, tweaking every setting manually has become an important part of managing temperatures. When you do get your chip and boot into the BIOS, one of the very first things to check are the idle voltages. Write these values down or take a screenshot of the BIOS itself, now that so many boards offer screenshot capabilities directly in the BIOS. Here's what you want to look for in order of importance:

vCORE: The main voltage for the CPU cores. Stock values can vary from 0.95 V to 1.15 V.

vCACHE: The main voltage for the ringbus and L3 cache. Stock values can vary from 0.95 V to 1.15 V.

VCCSA: Contains the memory controller, the PCIe controller, and other I/O domains. This is the main System Agent's domain voltage. The stock value sits somewhere between 0.800 V to 0.950 V, with most seen so far sitting between 0.850 V and 0.900 V.

The next two voltages are different parts of the System Agent domain, separate from the main VCCSA voltage. There is not a lot of information on what these voltages are for, but they are, like the "VTT" value of past platforms, helpful when scaling up the BCLK.

VCCAIO: This is the analog I/O voltage. So far, stock values range from 1.000V to 1.050V.

VCCDIO: This is the digital I/O voltage. So far, stock values range from 1.000V to 1.050V.

The next voltage, VCC-in, is very important because all other voltages already listed are only relevant once it is considered.

VCC-in: This is the input voltage to the FIVR, which stands for "Fully Integrated Voltage Regulation". It can range from 1.650 V to 1.850 V at stock. Most chips I have had my hands on so far, and the chips of those I've spoken to, all seem to run at 1.750V while in the BIOS. A chip with a 1.75 V FIVR and stock CPU voltage of 1.025 V should OC a bit better than one with a 1.80 V FIVR and a stock CPU voltage of 1.025 V.


Once you have recorded those voltage values, or the voltage values you could get your hands on, as not every board monitors all voltages in the BIOS, you'll want to keep that piece of paper close because the voltages relate to one another in quite important ways. I will go into a bit more detail momentarily but want to cover the last item you need to pay attention to on your initial boot first—your CPU temperature in the BIOS. If your BIOS monitors CPU temperatures, jot yours down next to those voltages.