The mount is set up perfectly and a big copy still crawls. Before blaming the NAS or the protocol, walk the path the data actually takes - in most homes, one Wi-Fi hop is quietly setting the speed for everything.
A mounted folder is not a cable between two disks. It is a live conversation: PC to router, router to NAS, request and answer for every piece of every file. The slowest hop in that chain is your copy speed, and the mount itself adds almost nothing on top. That is why the honest fix order is: grade the chain first, wire what you can, and only then look at disks and settings.
👆 Read the chain, not the NAS. One Wi-Fi end makes the whole path a Wi-Fi path, whichever direction the files travel.
Ask one question for each end: how is it connected right now? PC wired and NAS wired is the fast layout. If either end is on Wi-Fi, that hop is the ceiling for every copy - the other end's gigabit cable cannot help. In crowded buildings, a 2.4 GHz Wi-Fi link is the usual ceiling; it shares its airtime with every neighbour and every other device you own.
For most people the entire fix is two Ethernet cables: PC to router or switch, NAS to the same router or switch. Wire both, copy one large file as a test, and compare with the Wi-Fi result. If the speed jumps, you have found your culprit and your cure in one step - no settings were ever involved.
Windows 10 and 11 and DSM 7 both speak modern SMB, and on a home network the protocol is seldom what limits you - the link is. Resist the urge to "tune" SMB versions or signing settings to chase speed; at best it changes nothing, and disabling signing trades away a real protection the newer Windows versions added on purpose. Fix the path first.
One honest clarification, because the names confuse people: the File Station mount in the video happens entirely on your local network and never uses QuickConnect. QuickConnect is Synology's relay for reaching the NAS from outside your home. Local mounting is the fast arrangement precisely because the traffic stays at home - if your local copies are slow, the problem is inside the house, not on any Synology server.
Watch the video for the mount itself - then use this page's chain test before deciding anything about the NAS is slow.
▶️ Watch Full VideoTwo reasons combine: Wi-Fi behaves differently in each direction in a busy environment, and a copy is limited by both the reading disk and the writing disk. If one direction involves the Wi-Fi hop or an older, fuller drive, that direction is the slow one.
Only if the router or Wi-Fi hop is the current ceiling AND both the PC and the NAS can connect at the faster rate. A new router cannot speed up a NAS that is still on a weak Wi-Fi link, and it changes nothing for two wired devices that were already fast.
Not in any way you will notice. The PC simply answers file requests when the NAS asks. The load appears only while files are actually being copied, and it is the ordinary load of serving files - the same work the PC does for any network share.