I'm sure binning is a factor. They're likely on the edge of the manufacturing process with the 3950X. They probably can get enough to satisfy the demand over time, but demand will exceed the supply for a while.
I didn't realize Amazon was basically allowing people to backorder/pre-order them now. Your comment left me with the impression that the pre-orders at Amazon come and go. It seems like Amazon is continually allowing pre-orders since 12/26 (per nowinstock).I was able secure a pre-order through Amazon for a 3950X tonight. Their ETA won't have it arrive until Jan 18th though. I watch every day and the supply is still very limited at MSRP.
How are you getting notified of the Amazon pre-orders going up? At this point I might sit tight until the 4xxx series. I spent a lot of money in the past month or two on stuff not PC related. I could still get a new system, I not broke but tapping the brakes might not be a bad thing... Also, big FP improvements (up to 50%) in Zen 3 would favor my workloads. It will be interesting to see what AMD demos at CES.I just checked and they still have two. Another Amazon alert said they have more pre-order that will ship in 1-2 days. Mine arrived earlier this morning ahead of schedule.