A this point I think its worth to try a netinstall (
http://wiki.mikrotik.com/wiki/Manual:Netinstall), save another export to your PC first, this time omiting hide-sensitive parameter.
I'd advise to install 6.35.30
Once the router is netinstalled, import the .rsc export back; to do it you may either import it, or simply copy and paste its contents (CLI commands) onto a New Terminal.
This process re-formats the NAND and re-installs ROS, guaranteeing a "sane" state to begin with.
Where are the ethernet network devices wired to? All directly to the Hap? Or there is any additional switch?
OK, I'll try the netinstall, there's nothing to lose
But this is a brand new hAP ac. Straight from the box, Quick Set and nothing but problems with "wired" and everything works perfectly with wireless connections.
I do have a 16-port switch, but at the moment it's not connected to hAP, I tried to eliminate all "foreign elements".
I already installed 6.35.30 and I'm now getting about 15-20 Mbps almost every time I test it. But if I use a wireless connection on the same computer, I get 30 Mbps EVERY time. Sooo frustrating
I would even live with the lower speed if it worked consistently. But streaming and downloading stutters.
If wireless was giving me the same problems, I would look for MTU issues or something, but switching to wireless, evertyhing is great. Switching to the old router with wired connections, again, everything works great.
Maybe it's an issue with compatibility with my ISP's router (used in bridged mode), but then, why wireless works perfectly?
In my opionion, it's either problematic hardware or something stupid in the configuration that no one notices