- Speedtest on desktop with 802.11g:

- Speedtest on desktop with 802.11n:

- Speedtest on laptop with 802.11n:

- Speedtest on server (wired):

These are all on the same router (ASUS RT-N56U).
Also, the desktop doesn't seem to like using DHCP any more.
Scans with
sfc, Microsoft Security Essentials and Malwarebytes both said clean.