It's definitely because of single channel.
1 hour ago, Cereal5 said:
You're most likely running out of RAM in most of those games. I'm surprised you bought the parts you have and only managed a single stick of 8GB RAM. That, and it being single channel, are the most likely problems, though the CPU load at 100% is kind of a head scratcher. Do you have some programs running in the background? Maybe an anti-virus, or windows update?
Pretty much all latest AAA titles can utilize 16 threads, especially games like BF1 and 5, which are known to be CPU heavy. I get 100% usage on a 9700k, so 100% on a 8600k is completely normal and expected. It's only 6c/6t.