Overclocking with our Z790 APEX:
Choosing your DDR5 kit according to memory chips :
As was already the case for 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 Corsair Dominator Titanium 7200 MT/s CL34 kit is equipped with Hynix chips. But beware, there are Hynix M-die chips, the first to be introduced, and above all today’s Hynix A-die chips, which allow you to increase frequency more easily.
It’s hard to generalize, especially with the arrival of 2 x 24 GB kits, but in most cases, kits between 6,000 and 6,400 MT/s are Hynix M-die, and from 6,600 MT/s upwards, they’re almost all Hynix A-die. As you can see, our kit is a model with A-die chips, which we hope will give us good overclocking performance.
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. Don’t panic, we’ll come back to this in detail in our guide to overclocking Alder Lake and DDR5. If your PMIC module is not locked, by activating ” High DRAM Voltage Mode “, you’ll have access to voltages down to 2 volts. Now it’s time to overclock this Corsair 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 profiles available in the BIOS, which were a good basis on which to work. However, since the arrival of Hynix A-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 profile at 7600 MT/s CL36 and one at 8800 MT/s. The 8800 profile is out of the question due to our CPU’s IMC, which despite being already very good, is capped at 8700 MT/s. It is therefore impossible for us to reach this frequency. We’re currently looking for a 14900K with a very good IMC, so wait and see.
Step 2: our profile at 8400 MT/s and 8600 MTS in CL34
We’ve got a profile ready, and it’s set to go to 8400 MT/s and 8600 MT/s in CL34. Let’s test it and see how it performs. Let’s start with the 8400 MT/s CL34, which will require a VDD of 1.76 volts and a VDDQ of 1.64 volts. We found it very difficult to be stable with the CL32, so we stuck with the CL34.
As you’d expect, throughput in AIDA64 is through the roof, with read speeds reaching 133,270 MB/s and a memory score of 15,850 points in Geekbench3. However, it is still possible to optimize these results, and in particular the memory score, by increasing the uncore frequency, for example. Here’s our performance at 8600 MT/s in CL34.
Performance and throughput are still improving! Let’s see what else we can do to raise the score. So we’ve increased the BLCK frequency to 102 in order to raise the memory frequency to 8680 MT/s and the uncore frequency to 53x.
Needless to say, we’re on the verge of BMI and stability is rather precarious. We can’t wait to get our hands on a processor with even better BMI. Despite this, the performance speaks for itself and we can’t help but be fully satisfied with the performance obtained, whether with XMP profiles or overclocking.
