Overclocking on our APEX Z790 Encore:
Choosing your DDR5 kit according to memory chips :
As was already the case with DDR4, if you want to clock your memory, certain brands will benefit from better potential. At present, the kits announced by the various brands benefit from either Micron, Hynix or Samsung chips. The latter two brands will be the most interesting. As you can see, our G.SKill Trident Z5 RGB kit, clocked at 8000 MT/s CL40, is equipped with Hynix chips. Unlike our last kits, these are not Hynix A-die chips, but the new Hynix M-die chips. These have the particularity of rising more easily in frequency, but being more complicated to tighten in terms of timing.
To take advantage of high-frequency kits, it’s best to be equipped with a motherboard dedicated to this type of kit, and in this game, the ROG APEX Z790 is certainly the best. It features two memory slots to facilitate memory overclocking. You’ll also need a processor with an excellent IMC(Integred Memory Controller). Beware: a processor may have excellent overclocking potential but, on the other hand, a disappointing IMC. These two factors are independent of each other.
Key DDR5 voltages :
For memory overclocking, there are 5 key voltages. These are the voltages that will have an impact on overclocking and therefore on frequency rise or timing tightness. 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’s where you’ll find these voltages in the BIOS of our ROG Maximus Z690/Z790 APEX.
Please note that, depending on the type of memory chip (Micron, Hynix and Samsung), the balance between these different voltages is different. If your PMIC module is not locked, by activating ” High DRAM Voltage Mode “, you’ll have access to voltages up to 2.00 volts. Now it’s time to overclock this G.SKill DDR5.
Step 1: use available BIOS profiles
It’s a strange thing to say, but a few months ago, we were happy to have the BIOS profiles available as a good basis for our work. However, since the arrival of the Hynix A-die and now the new Hynix M-die chips, the frequency of kits has exploded, and in the end, the profiles in the BIOS are lower than the current frequency of our kit. There’s a 7600 MT/s CL36 profile and an 8800 MT/s profile for Hynix A-die chips, so we’ll have to build our own profiles.
Step 2: 8800 MT/s CL36 target
This is our second objective: to reach the 8800 MT/s CL36 frequency, since this type of chip should be able to do this quite easily. We set up the BIOS, modify voltages, timings and subtimings, and off we go. For your information, the SA voltage is 1.33 volts, the VDD at 1.59 volts, the VDDQ at 1.47 volts, the IVR at 1.375 volts and finally the MC at 1.425 volts. This is a profile that allows us to compare kits in overclocking.
The good news is that it starts up without any difficulty and our two benchmarks go straight through. We ran several of them in a row, and there were no worries about stability. As you’d expect, throughputs in AIDA64 explode, with read speeds reaching 137410 MB/s, while memory scores in Geekbench3 rise from 13827 points, at 8000 MT/s, to 16370 points, at 8800 MT/s.
Step 3: 8888 MT/s CL36 with 101 MHz BCLK
As my tests progressed, I found it impossible to boot up to 9000 MT/s. The only way to continue increasing the frequency is to increase the BCLK to 101 MHz. This will have the effect of increasing the memory frequency at the same time.
So here we are, with the same voltages/timings at 8888 MT/s. Performance continues to improve, with AIDA64 reading at 138430 MB/s and Geekbench3 memory score at 16556 points.
Step 5: Creating new profiles
At the start of 2024, we’d like to develop our overclocking tests for DDR5 memory kits, whether Hynix A-die or Hynix M-die. We have prepared test profiles that will enable us to evaluate the overclocking capabilities of the kits by checking their stability. We were able to reach a frequency of 9000 MT/s, but not in a stable way, as we’re certainly reaching the limits of our processor.
We’ve also seen that the AMD Ryzen 7 8700G processor seems to have an excellent IMC, enabling higher frequencies with memory kits. We’ll be trying to get our hands on a copy to test this and, why not, include it in our memory overclocking tests.
