Overclocking on our X670E Gene:
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 EXPO kits announced by the various brands are only equipped with Hynix M-die chips. These chips have a good overclocking potential on Intel platforms. Attention, since a few weeks, there are also Hynix A-die chips which allow to go up in frequency more easily but no EXPO kit currently has them.
DDR5 EXPO “key” voltages:
This is really different from what happens with Intel. Here, four voltages seem to impact overclocking. The two main ones are the DRAM VVD Voltage and the DRAM VVDQ Voltage . During our overclocking tests, we also became aware that two other voltages could have an impact, these are VDDP and VDDIO.
We are just discovering overclocking on the AMD platform and it is quite different from what we have on an Intel platform. We’ll talk about it again in the overclockingsection.
Step 1: A little theory to get started
Well, let’s start with a theoretical reminder since there are some changes with the arrival of the ZEN 4 architecture as far as memory is concerned. While for the Ryzen 5000, the standard was to keep a 1:1:1 ratio between mclk:uclk:fclk, this will change with the Ryzen 7000. Indeed, they adopt the DDR5 memory. This one sees its frequency increasing, which implies changes in these ratios. AMD now recommends for AM5 motherboards in DDR5 a 1:1 ratio for the mclk:uclk and to finally leave the fclk in AUTO which will automatically set it to 2000 MHz. Theoretically, this is how it will behave:
- DDR5-4800 will give with the new 2400:2400:2000 MHz ratios (mclk:uclk:fclk)
- DDR5-5200 will give with the new ratios 2600:2600:2000 MHz (mclk:uclk:fclk)
- DDR5-6000 will give with the new ratios 3000:3000:2000 MHz (mclk:uclk:fclk)
Well, it may seem a bit complicated like that, but we’ll explain it all to you. First of all, don’t panic, if you activate your DOCP or EXPO profile in the BIOS, everything will be set up automatically. The explanations we give you here are for those who want to overclock their memory kit.
Step 2: fclk, uclk and mclk
The fclk is the frequency of theInfiny Fabric which can be, since the previous generation, controlled independently via the BIOS parameters. By default, this value is set to AUTO mode and it is the motherboard that will manage its frequency to ensure the stability of the system. Its maximum frequency is around 2100/2200 MHz but it also depends on the quality of your processor, but that’s the lottery that will decide. The mclk also sometimes called ” memclk ” is the frequency of your memory kit and the uclk is the frequency of the memory controller.
You should also know that if you exceed the frequency of 6000 MT/s with your memory kit, automatically the frequency of the memory controller (uclk) should switch to a ratio of 1:2 always in order to ensure system stability. AMD indicates that the best performing frequency and ratios are 3000:3000:2000(mclk:uclk:fclk). This is the reason why all DDR5 EXPO kits are 6000 MT/s.
We tested our DDR5 kits with a frequency higher than 6400 MT/s and none of them agreed to work.
Step 3: overclocking via profiles in the GENE BIOS
The ROG Crosshair X670E motherboard has three memory overclocking profiles compatible with Hynix kits in 2 x 16 GB. 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.
We’re going to test each of these profiles to see the impact they have on the performance obtained with our original kit and you’ll see that it’s well worth overclocking!
Step 4: 6200, 6400 and maybe more?
To load the profiles, nothing could be easier, just click on them and validate. Be careful though, if the timings and the voltage are set automatically, you will have to change the frequency of the kit manually. For the first profile, we had to change the frequency in the BIOS from 6000 to 6200 MHz.
The profile 6200 1.4 volt and 6400 1.4 volt pass without problem. The second profile at 6400 MT/s uses a voltage of 1.5 volt. If our Corsair kit refused to boot with a voltage higher than 1.435 volt, it is not the case for our GSKill kit. The profiles present in the BIOS tighten up the subtimings very strongly which should bring a real gain in our benchmarks.
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. We also added a new profile based on the 6400 MT/s profile where we went from CL32 to CL30 for the tCL.
The overclocking potential of this kit is excellent and thanks to the profiles, the performance gain is very interesting. We are surprised that manufacturers do not opt for tighter subtimings. Here are our two best scores under AIDA64 and Geekbench 3.4.4 with FCLK frequency increased to 2200 MHz, further optimized subtimings and a VDD/VDDQ voltage of 1.53 volt.
We continue our exploration of overclocking on this type of kit with the goal of passing the 100000 MB/s mark in reading.
