This comment section contains tears of the Nvidia fanboys :P
It's a GPU, you win in some games and lose in others. Nvidia has done its share of shady practices; Hello? Nvidia gimpworks anybody recall? AMD tends to make its features opensource, therefore, developers and competitors can use and...
Yup, upping the voltage or lowering the clock speed will help stabilize. Just be mindful that AMD suggests no more than 1.45v as absolute max voltage for ryzen, and 1.35v as safe limit for 24/7 machine.
You can also safely up your RAM voltage to 1.35v.
I almost got my Ryzen parts at MC until I find that they have shortage/small selection of AM4 Mobos at my local stores. With the given options plus tax, it was actually more advantageous to purchase online.
The store also told me that bundle discounts are voided if I price match online prices.
Is your BIOS up-to-date?
Are you running your RAM on XMP profile or on Auto?
What program are you using to monitor your CPU temps?
Try AIDA64 stress test.
Has the problem reoccurred since you downclocked to 3.7?
1. 30 mins under P95 is NOT indicative of system stability. Try 3-4 hours. Many Overclockers are also shifting to AIDA64 stress test. My guess is that the OC, either CPU, RAM, or both, was never stable to begin with.
2. Is your BIOS...
No, the 850 BQ is crap made by HEC. Go for the B2, G2, or GS.
In fact, you don't need a 850w. Get this one instead. https://www.bhphotovideo.com/c/product/1161835-REG/sea_sonic_electronics_s12ii_620_bronze_ss_620g_s12ii_series_ss_620gb_active.html
But the problem is Ultra, which is made by Andyson. Their PSUs are either hit or miss.
Not all 750w PSU are created equal. Reference this list.
http://www.tomshardware.com/forum/id-2547993/psu-tier-list.html
http://www.microcenter.com/product/468414/SE2717Hx_27_IPS_LED_Monitor_w-_AMD_FreeSync
24" 144hz TN
or
http://www.microcenter.com/product/470186/KG240_24_Full_HD_FreeSync_Display_Monitor
27" 60hz IPS
Might upgrade to Fury or 490 in the near future.