Overclocking on our Z790 APEX:
Choosing your DDR5 kit based on memory chips :
As was already the case with DDR4, if you want to clock your memory, some brands will have better potential. Currently, the kits announced by the various brands have either Micron, Hynix or Samsung chips. The latter two brands will be the most interesting. Our Teamgroup Delta RGB 7200 MT/S kit is equipped with Hynix chips as you can see. But be careful, there are Hynix M-die chips, the first ones that came out, but especially today Hynix A-die chips that allow to go up in frequency more easily. A small but important note: our ROG Z690 APEX is a “new version” of 2022 which eliminates the problems encountered with memory overclocking above 6600/6800 MHz.
DDR5 “key” voltages:
For memory overclocking, there are 5 key voltages. These are the voltages that will have an impact on the overclocking and therefore on the frequency rise or the tightening of the timings. These are the CPU System Agent Voltage (SA), the DRAM VVD Voltage, the DRAM VVDQ Voltage, the Memory Controller Voltage and the IVR Transmitter VVDQ Voltage. Here is where these voltages are located in the BIOS of our ROG Maximus Z690 APEX.
Beware, depending on the type of memory chips (Micron, Hynix and Samsung), the balance between these different voltages is different. Don’t panic, we will come back to this in our guide on overclocking Alder Lake and DDR5. If your PMIC module is not locked, by activating ” High DRAM Voltage Mode “, you will have access to voltages up to 2 volts. Let’s go for the overclocking of this DDR5 from GSKill.
Step 1: Change your processor and motherboard
Why? Simply because the IMC(Integrated Memory Controller) on my 13900K is much better than the one on my 12900K. Now integrated into the processor, the IMC allows for more direct and faster RAM management than when the memory controllers were on the motherboard. As with overclocking, there is a “lottery” and some processors benefit from a better IMC that allows them to handle higher memory frequencies. Since in overclocking we are going to increase the frequency, especially with A-die chips, we might as well take the best CPU at this little game. We will also do a performance test with the XMP profile and our i9-13900K in order to have a basis for comparison for our overclocking results. You will also see that we will disable the E-core at some point in order to be stable in higher frequencies.
Step 2: APEX profile at 7600 MT/s CL36
The ROG Maximus Z790 APEX motherboard has a profile at 7600 MT/s which we will also use to test the next kits. To do this, go to the BIOS in the “Extreme Tweaker” section and choose “Memory Presets”. There, you will find a whole series of memory profiles and notably the famous Hynix 7600 MHz.
It is therefore him that we will activate for our test. Attention, if the timings and the voltages are automatically modified, it is not the case of the memory frequency. So you should not forget to choose 7600 MHz.
We did our tests with this profile and it was perfectly stable. We’ll talk about performance a little further down when we summarize the performance of this GSKill Trident Z5 RGB 6800 MT/s CL34 kit.
Step 2: 8000, 8200 or even 8400 MT/s?
We have set up a series of profiles that will allow us to test the kits with Hynix A-die chips. We will see if they are capable of holding these frequencies. We have three profiles to test at 8000, 8200 and 8400+. Of course, the voltages and timings will be different for each of these profiles. The 8000 profile passes without any problem as well as the 8200 MT/s profile. If the 8400 MT/s profile arrives in the OS, it did not prove to be stable enough and did not allow us for example to finish an AIDA64 memory or a Geekbench 3.
Below is the capture in Windows 10 of the 8400 MT/s frequency. It would surely be possible to find some stability for benchmarks by releasing some timings. Increasing the voltage does not improve anything because then impossible to reach in the OS.
Here is a table that shows the different scores we obtained at these different frequencies under AIDA64 and Geekbench 3.4.4 by comparing to the stock frequencies. 
The overclocking potential of this kit is excellent since we can easily reach 8200 MT/s in benchmarks while the base frequency is, remember, 6800 MT/s.
