I'm trying to upgrade to Ryzen and have the following new bits:

X370 Killer SLI/ac

Ryzen 5 1600

Mushkin 2666 RAM model MRA4U266GHHF8GX2 (2x8gb)

WD Blue M.2 500gb ssd

and will be reusing my AMD RX 460 gpu.

I've been running into POST problems the whole way. With just CPU socketed in and fan plugged in, I get 3 beeps, as I would expect. When I plug in 1 stick of ram, I get 3 beeps followed by 8 beeps. Then I re-read the AM4 memory slot rules that came with the motherboard, and decided to try plugging in both sticks of ram in A2 and B2. That led to 6 beeps and 8 beeps (unless it is 3 beeps, immediately 3 more beeps, and then 8 beeps?). 

That's basically where I am now, and I have no idea what to try next. I got in touch with the ASRock tech support folks by email and was told to clear CMOS and try plugging things in one at a time, which I've done to no effect. I'm thinking now that it might be a RAM issue, but all the reviews I've read have had no trouble with Ryzen and that model of memory. 

Edit: Also, it makes no difference whether I have the GPU installed or not. 

Anyone have a suggestion for what to try next?