RN104 Slow Read Speeds

Thanks for the replies.

The NTLM issue - it has been happening with windows 8 machines and now windows 10. I can't find any settings to manage that on the nas. The SMB plus app only allows me to select which version of smb it uses.  That kb article is the setting I need to change but I fail to see why I need to modify every windows 8 or 10 machine in order for it to access the shares.  I also have the shares set to anonymous access but it still also prompts me for username and password the first time I try and access the shares...

With regards to the slow read performance, I have narrowed it down to this machine, and only for read operaitons from the nas.  For example, I can download from the NAS using a laptop on wifi ac at 50MBps.  On the machine with issues, I can download from the internet and from other local machines at full 100mbps, and I can upload TO the nas at the same speed, I simply cannot download from the nas at anything near full speed.

What can I check that could be affecting just downloads from the one nas device to this one machine and nothing else?  All other transfers are at full speed?

Edit just to add a little network info. Router is a Netgear R7000. Nas connected to R7000 gigabit port. PC connected to 500mbps TP Link powerline plug (synced at ~350mb, has 100mb ethernet ports). As mentioned above I can achieve full 100mbps speed downloading from the internet or from another local machine on this network, and can upload to nas at that speed. Just not download from it, which goes at 3 - 4 MBps.

Jumbo frames not enabled, MTU is 1500. I will try a direct connection from NAS to pc later but anything I can try in the mean time appreciated.