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, leaving all settings at their XMP defaults and then increasing the frequency until the system loses 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 that allows the system memory to run in a synchronous 1:1 mode with the CPU memory controller, or a 2:1 ratio. Intel 12th Gen Alder Lake brought DDR5 support along with an additional 4:1 ratio and continuing DDR4 support.

While the DDR5 JEDEC specifications start at 4800 MT/s, this does not prevent memory from operating a at lower frequency. Thus, memory kits are popping up for sale with XMP profiles of 4400 MT/s. However, the 1:1 ratio generally stops between 3600 and 4000 MT/s, leaving those lower-bin kits to suffer the same fate. My Core i9-12900K maxes out at 4200 MT/s, which isn't rare if going by the sheer amount of forum posts with many struggling to reach 3800 MT/s. It is safe to say that anything greater than 3600 in a 1:1 ratio configuration is completely dependent on the CPU memory controller.

Because DDR5 generally has a higher operational frequency, synchronously operating it in 1:1 is unlikely. That only leaves 2:1 as a viable option for any DDR5-based setup. The motherboards should automatically switch to the 2:1 ratio. If all else fails, you can manually set this in the BIOS.

Intel Results

With the Intel Core i9-12900K, I was not able to raise the frequency at all using the XMP settings at its default 5200 MT/s profile. Going down in latency also ended in a failed boot sequence. The next step was to raise the CAS to 40, which had it boot and pass stability tests at 5400 MT/s. The final push took 1.35 V, which brought 5600 MT/s under control. This is the stopping point. Neither voltage nor looser timings allowed me to boot any higher. It is hard to be disappointed at such an early stage of the product's life cycle because I am not sure what I was really hoping to achieve. I know that 6400 MT/s is possible with this ASUS ROG Z690 Hero and my CPU, leaving me to conclude that not much more can be done with this Corsair Vengeance kit equipped with Micron memory.