Hey! My Ryzen R5 3600 arrived today, and I just installed it! Board is a Gigabyte B450 AORUS PRO WIFI, a decent mid-grade B450 board, with BIOS update F40 with explicit CPU support for 3rd-Gen Ryzen CPUs.
So, it's basically working, put on my stock heatsink that I had on there, that was from an R3 1200. (*I sold my R5 1600 heatsink, the nice 95W TDP one, with the R3 1200 rig I sold. Sigh.) The heatsink that came in the box with the 3600 was no better, and looked possibly slightly smaller, if you can believe that.
HWMonitor shows single-core/idle boosting to 4.2Ghz. Hovering around 2.2Ghz at idle. Haven't tried an all-core load yet, will update.
Also, sadly, I lost two SATA ports on the board. I think that they were the SoC SATA ports driven off of the CPU. Not sure if I bent a pin or two on the CPU when I dropped it in (would be rare for me, it went in without force), or most likely, an immature AGESA or Gigabyte UEFI, that didn't quite "wire up" the SoC SATA ports. So my other two 512GB SSDs are inaccessable for now.
All the B450 chipset SATA ports (0-3) are working correctly, or at least, all detected.
RAM is 4x8GB Team Group Vulcan DDR4-3000, all running happily at XMP 3000 speeds, not sure what CAS, probably 16-18-18-38 or 40. They all ran successfully in this board with the R5 1600 too, at XMP speeds. This board has been great for RAM clocking.
Seems maybe a little faster? Hard to tell. I'm happy though. Only $200 for an upgrade, now it shows me running 4.2Ghz, rather than 3.4Ghz.