Hey BC! I have a very annoying problem that i cannot sort out... hopefully someone here can help.
A couple months ago I began having some weird bandwidth issues on a Win8.1 system i built less than a year ago.
Long story short:
I discovered the 50Mbps from my ISP was showing up as about 3Mbps on speed tests. After some troubleshooting i realized it was only on this particular system. I rolled back the driver and it resolved the issue (temporarily). Since it returned, i have tried every driver with the same results. I have replaced the WLAN card, i even replaced my asrock fm2a88x-itx+ MOBO after i realized the LAN port was defective (luckily i'm still under warranty). My router as well has since been upgraded to an ASUS RT-AC56U AC1200. I have checked my router and there aren't any limits set.
The reason why i am leaning towards some kind of infection is because i recently recognized some weird traffic on my system. First i noticed some traffic from SVChost going to an Akamai IP. I know many progs use there cloud services but i don't believe i even had any. I did remember i installed some video player for showtime or some other on demand video service which i removed and haven't seen the activity since. Not sure if related. I downloaded Wireshark but i've never used it before and am a little lost.
However the issue remains. I have ran all kinds of virus scans and have produced nothing (ms defender, bitdefender, malwarebytes, rkill, adwcleaner, hitman, jrt).
At this point it HAS to be virus or OS related. I am stumped. I am considering reloading my Win8 OS but would really prefer not to.