3600 MHz RAM on AMD B550

Up until a couple of weekends ago, I’d been running my Corsair Vengeance LPX 2x8 GB RAM at 3600 MHz on my ASRock B550M Steel Legend and AMD Ryzen 5 5600X. In fact, I did even better than XMP settings, with a stable system even though I pushed RAM timings by reducing CAS 18 to CAS 16. Then, I upgraded my motherboard BIOS to AMD AGESA AM4 v2 1.2.0.2... and now I can no longer run at 3600 MHz!

I have no solution, just sharing my experience. I don’t overclock my CPU. My RAM is rated at 3600 MHz (“optimized by Ryzen”) and I overclock the timings. But overclocking is not the problem, it’s simply that this CPU-motherboard-BIOS combination can no longer support RAM at 3600 MHz.

Prior to updating my ASRock motherboard BIOS (from v1.62 to v2.0), I had issues with the M.2 Intel Wi-Fi 6 AX200 module (perhaps USB related): Bluetooth often disconnects, but worse is the fact the card is sometimes not found when booting, and reboots don’t immediately help. So I figured I’d update to BIOS v2.0, AMD chipset driver v2.13.27.501, and Intel WiFi/BT drivers 22.40.0 (before I was using Microsoft’s standard drivers).

After updating the BIOS firmware, I applied the RAM XMP profile (3600 MHz at 1.35 volts with timings 18-22-22-42 and 1:1 clocks. And the motherboard would NOT even post! I really panicked, as I could not even get into BIOS to edit the settings. Luckily there is a CMOS reset button at the back of the motherboard.

After much fiddling and many reboots later, trying to lower timings, increase voltages, etc., I found that other users where suggesting topping out at 3200 MHz for the 5600X (depending on number of RAM sticks and ranks, but what do I know about these things). So I tried a small reduction from 3600 MHz down to 3534 MHz, and what do you know, the system could boot, and MEMbench tests are stable at both the standard 18-22-22-22-42 timings and my pushed 16-18-19-16-36 timings. Huh.