So here's the thing... Last week I went to MicroCenter and purchased the ASUS Prime B450 Plus, Ryzen 5 2600, and 16gb Corsair Vengeance LPX. For the love of god I cannot change the sub timing on that ram. Every time it failed, I had to swap ram from A2/B2 to A1/B1 to load into bios. The worst part about this experience is when ram is in A1/B1 DOHC will not recognized the frequency and timing until I switch it back to A2/B2. So I actually spent several hours tinkering with the ram timing. I don't know if it's the Asus mobo or the Corsair (Micron D-die) that's causing this problem.
Yesterday, I checked MicroCenter website and they had the MSI B450 Tomahawk in stock. I called to reserve it and ask them to exchange the Corsair for a G- Skill. Got home and installed the mobo, rams, and CPU. Checked ram info on Thaiphoon and ran DRam Cal for Ryzen. Changed the sub timing and it instantly load into Windows without any problem.
Tested AC Odyssey and notice min/avg FPS increase on AC Odyssey benchmark. This was on stock CPU speed. I was able to achieved that same performance with Asus mobo and Corsair when ram was at 3400mhz (DOHC profile) and CPU @ 4.2 Ghz. I wanna keep tinkering with it but if something goes wrong i just don't want to spend several more hours troubleshooting it unless 3400mhz fast preset is worth the time and performance.