Review : ROG Maximus Z790 APEX


CPU overclocking:

When you say new platform, you have to adapt to it, but since we are quite close to the Z690 chipset, we shouldn’t have too much difficulty. We will just have to take into account the new specificities of the processors in terms of frequencies.


Before starting, it is necessary to have one or more reference scores with our i9-13900K at stock frequencies , i.e., without having made any modification except having activated the XMP profile. It is also very important to have at hand a sheet that will allow you to note all the tests you will perform as well as the results or failures. Personally, I have hundreds of sheets of my tests on which I sometimes go back to know how the processor behaved on such motherboard or in such test conditions. My own little bible.

For H24 overclocking, it will of course be necessary to take more time to fine-tune the voltage in order to provide it with the minimum necessary, but also to adjust each core independently if you want to take advantage of the maximum performance.

Load-Line Calibration in BIOS:

In the case of Rocket Lake, even if Asus advises a Level 4 for overclocking, I opted for a Level 7 in order to have the least vdroop possible.
Basically, I want the voltage chosen to be as close as possible to the load voltage. In the tables below, you can see the selected voltage, the effective voltage in idle and finally in load . The readings are made with a multimeter at the PCB of the motherboard. It is very important to know the real voltage brought to the different components but especially to your processor.

Overclocking under watercooling in different steps:

As usual, I will start the tests by choosing, via the BIOS, a starting frequency applied on the 8 P-Cores of the i9-13900K. I chose a starting frequency of 5500 MHz with a multiplier of 55, a BCLK of 100, a voltage of 1.20 volt and a Level 7. All the other options are in AUTO. I already had the opportunity to test my i9-13900K and it is far from being a war lightning unfortunately.

The idea is then, in the OS, to test the stability on several runs of Cinebench R23 multithread . If it’s stable, I increase the frequency by 100 MHz while checking the stability again. If the benchmark crashes, I increase the voltage by 0.05 volt increments in order to regain a stability allowing to run the benchmark. The objective is to get a “quick” idea of the maximum benchmarkable frequency.

Here is what we obtained for the i9-13900K. As you can see, we were very quickly limited by the temperature and this despite a fairly low voltage.

Our best score is 42329 in Cinebench R23 but with temperatures that are between 85 and 88°C. Our copy is unfortunately not a gold processor and behaved well under LN2. I’m waiting for the 13900KS to arrive in order to try to get my hands on a goldprocessor.