Overclocking on our Z790 APEX:
Choosing your DDR5 kit based on memory chips :
As it was already the case for DDR4, if you want to clock your memory, some brands will have a better potential. Currently, the kits announced by the various brands have either Micron, Hynix or Samsung chips. These last two brands will be the most interesting. Our Corsair Dominator Platinum 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.
DDR5 “key” voltages:
For the overclocking of the memory, 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 Z790 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 Corsair.
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 7600 MT/s profile that 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 voltages are automatically modified, it is not the case for 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 Corsair Dominator Platinum RGB 7200 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.
Here is a table that shows the different scores we got at these different frequencies under AIDA64 and Geekbench 3.4.4 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, 7200 MT/s. Now, this is not our best kit in overclocking since the award goes to the Teamgroup kit. Now, the chips are probably a little less powerful since, as you know, the XMP profile needs 1.45 volts at 7200 MT/s whereas the Teamgroup only needs 1.40 volts. We will propose you in the next weeks an article dedicated to a stable profile which could be between 7600 and 8000 MT/s for Hynix A-die chips.
