Tweaking for Speed

With testing out of the way, I endeavored to see if these sticks have any headroom. For Intel, I kept the same procedure I have been using: I used the XMP profile and increased the frequency until the system lost stability. After finding that limit, I manually tweaked for the maximum frequency and lowest possible timings. Voltage modification from stock is allowed. After all, this is overclocking!

The 11th Gen Intel Core processor paved the way for things to come. With the introduction of the memory controller Gear Ratio, it allowed the system memory to run in a synchronous 1:1 mode with the CPU memory controller, or a 2:1 ratio. With the release of Intel's 12th Gen Alder Lake based processors came DDR5 support and the additional 4:1 ratio.

1:1 ratio generally falls between between 3600 and 4000 MT/s for Alder Lake CPUs. This is completely dependent on the CPU memory controller and supporting voltages. In rare instances, higher-end motherboards can increase this slightly and offer better overall compatibilty. My Core i9-12900K maxes out at 4133 MT/s, which is rare if going by the sheer number of forum posts about many struggling to reach 3800 MT/s. It is safe to say that anything greater than 3600 MT/s will require a bit of hands-on tuning.

With this information, Intel 12th Gen Alder Lake paired with DDR5 will gain the most from the highest-possible frequency without giving up the benefit of the increased bandwidth it can provide. Because DDR5 has a higher operational frequency and dual 32-bit data bus, synchronously operating it in 1:1 is unlikely. That only leaves 2:1 and above as a viable option for any DDR5-based setup. The motherboard should automatically switch to the 2:1 ratio. If all else fails, you can manually set this in the BIOS.

Intel Results

Using the Intel Core i9-12900K and ASUS ROG Z690 Hero motherboard, I was able to reach 6400 MT/s with the DDR5-6000 XMP profile. No additional voltage adjustments to the System Agent (SA), vDD2 (memory controller), and TX VDDQ were needed. I was unable to successfully boot and stabilize 6600 MT/s even with a voltage bump to 1.4 V.

Having found the upper limit of what I can currently accomplish with this kit, it was time to lower the timings. Using other low-latency SK Hynix memory kits as a a baseline, I managed to set a few different configurations. These all required 1.4 V to pass stability tests. More can be done with higher voltages, but given their scarcity, I didn't want to destroy any DDR5 memory kits just yet.