Windows driver maybe causing it then, are you able to remove the device and drivers from device manager then connect wifi and let windows update find the best driver?
Failing that, get the proper driver from the motherboard manufacturers website.
I removed/uninstalled the Ethernet/LAN device and drivers from the device manager and then checked windows update, restarted and checked again to make sure and there didn't seem to be any drivers via the windows update. However, it did automatically set up the device again after restarting my PC, and I tested the internet, installed the manufacturer's driver and tested again, and all the tests came back with the same speed results (seemingly locked to about 280ish).
Yep your narrowing it down. So it's some software which is throttling your speeds. Now what that is who know but the AV/security stuff is first bet. You may even have a virus on your PC but it shouldn't be able to run in safe mode.
If you open up command prompt, cmd.exe and enter this,
tasklist > %userprofile%\desktop\processes.txt
Them upload the processes.txt file which should be saved to the desktop.
I tested it before with my antivirus and such uninstalled and it still came back with the seemingly capped speeds so I'm not sure if it is security/AV related, unless there'd be an alternative thing to test in that regard. Hopefully there wouldn't be a virus though, although there is the factor that safe mode should've avoided that being the case. Also, I ran the line in CMD to create a .txt with the list of processes, although I'm not sure how to actually upload the file itself if you meant that since I'm not too familiar with forum formats, but I'll include the text from the file in this post:
Image Name PID Session Name Session# Mem Usage
========================= ======== ================ =========== ============
System Idle Process 0 Services 0 8 K
System 4 Services 0 5,704 K
Registry 136 Services 0 92,784 K
smss.exe 456 Services 0 1,060 K
csrss.exe 764 Services 0 4,240 K
wininit.exe 852 Services 0 4,084 K
csrss.exe 860 Console 1 4,224 K
services.exe 924 Services 0 8,268 K
lsass.exe 944 Services 0 15,116 K
winlogon.exe 1012 Console 1 9,032 K
svchost.exe 744 Services 0 2,484 K
svchost.exe 768 Services 0 25,240 K
fontdrvhost.exe 84 Console 1 7,112 K
fontdrvhost.exe 968 Services 0 2,088 K
svchost.exe 1092 Services 0 14,580 K
svchost.exe 1148 Services 0 6,300 K
dwm.exe 1220 Console 1 57,520 K
svchost.exe 1452 Services 0 13,272 K
svchost.exe 1472 Services 0 16,368 K
svchost.exe 1480 Services 0 3,896 K
svchost.exe 1552 Services 0 8,724 K
svchost.exe 1560 Services 0 9,932 K
svchost.exe 1568 Services 0 10,384 K
svchost.exe 1692 Services 0 7,212 K
svchost.exe 1720 Services 0 3,816 K
svchost.exe 1800 Services 0 8,400 K
svchost.exe 1808 Services 0 5,908 K
svchost.exe 1988 Services 0 11,128 K
svchost.exe 2008 Services 0 13,032 K
svchost.exe 1196 Services 0 5,016 K
NVDisplay.Container.exe 2168 Services 0 15,360 K
svchost.exe 2200 Services 0 7,388 K
svchost.exe 2208 Services 0 7,444 K
svchost.exe 2288 Services 0 11,692 K
svchost.exe 2296 Services 0 3,752 K
svchost.exe 2304 Services 0 6,060 K
wsc_proxy.exe 2312 Services 0 7,860 K
svchost.exe 2440 Services 0 7,796 K
Memory Compression 2488 Services 0 72,588 K
svchost.exe 2548 Services 0 6,888 K
svchost.exe 2696 Services 0 21,952 K
NVDisplay.Container.exe 2720 Console 1 32,648 K
svchost.exe 2816 Services 0 5,576 K
svchost.exe 2824 Services 0 4,668 K
sihost.exe 3044 Console 1 23,804 K
svchost.exe 1200 Console 1 27,696 K
svchost.exe 3136 Console 1 36,776 K
svchost.exe 3144 Services 0 13,168 K
taskhostw.exe 3296 Console 1 13,948 K
AsusUpdate.exe 3304 Services 0 472 K
EzUpdt.exe 3312 Console 1 1,028 K
AISuite3.exe 3344 Console 1 10,692 K
svchost.exe 3376 Services 0 13,696 K
GpuFanHelper.exe 3424 Console 1 2,024 K
DipAwayMode.exe 3504 Console 1 1,016 K
svchost.exe 3572 Services 0 6,640 K
ctfmon.exe 3632 Console 1 13,580 K
WmiPrvSE.exe 3708 Services 0 37,284 K
svchost.exe 3960 Services 0 16,064 K
svchost.exe 4068 Services 0 8,216 K
svchost.exe 4076 Services 0 4,720 K
svchost.exe 1388 Services 0 5,904 K
svchost.exe 4112 Services 0 21,848 K
explorer.exe 4140 Console 1 141,748 K
svchost.exe 4360 Services 0 15,824 K
svchost.exe 4424 Services 0 13,608 K
AvastSvc.exe 4544 Services 0 154,064 K
svchost.exe 4704 Services 0 15,380 K
svchost.exe 4776 Services 0 15,540 K
WmiPrvSE.exe 4924 Services 0 13,192 K
wlanext.exe 5036 Services 0 14,224 K
conhost.exe 5076 Services 0 3,952 K
spoolsv.exe 5188 Services 0 10,412 K
svchost.exe 5244 Console 1 15,228 K
svchost.exe 5304 Services 0 5,676 K
svchost.exe 5448 Services 0 16,576 K
AsusUpdateCheck.exe 5456 Services 0 10,776 K
svchost.exe 5464 Services 0 25,764 K
svchost.exe 5472 Services 0 5,760 K
svchost.exe 5480 Services 0 3,512 K
svchost.exe 5488 Services 0 22,772 K
svchost.exe 5512 Services 0 3,952 K
Corsair.Service.exe 5520 Services 0 54,044 K
ibtsiva.exe 5528 Services 0 3,152 K
EvtEng.exe 5536 Services 0 14,144 K
svchost.exe 5544 Services 0 21,244 K
RegSrvc.exe 5568 Services 0 6,888 K
AsSysCtrlService.exe 5580 Services 0 6,152 K
RtkAudUService64.exe 5588 Services 0 6,628 K
NahimicService.exe 5596 Services 0 17,104 K
nordvpn-service.exe 5616 Services 0 36,480 K
nvcontainer.exe 5624 Services 0 32,624 K
atkexComSvc.exe 5640 Services 0 12,092 K
ZeroConfigService.exe 5648 Services 0 16,296 K
LightingService.exe 5656 Services 0 17,756 K
AsusFanControlService.exe 5676 Services 0 19,204 K
svchost.exe 5696 Services 0 5,696 K
OriginWebHelperService.ex 5700 Services 0 11,544 K
svchost.exe 5760 Services 0 6,832 K
dasHost.exe 6164 Services 0 11,820 K
svchost.exe 6264 Services 0 3,264 K
svchost.exe 6480 Services 0 6,880 K
svchost.exe 6700 Services 0 9,360 K
unsecapp.exe 7104 Services 0 9,664 K
rundll32.exe 7248 Console 1 6,060 K
svchost.exe 7892 Services 0 5,672 K
svchost.exe 8088 Services 0 5,852 K
dllhost.exe 8184 Console 1 5,268 K
StartMenuExperienceHost.e 7236 Console 1 88,000 K
RuntimeBroker.exe 8680 Console 1 33,588 K
Corsair.Service.CpuIdRemo 8796 Console 1 41,768 K
conhost.exe 8896 Console 1 4,168 K
SearchUI.exe 9096 Console 1 170,280 K
SearchIndexer.exe 9316 Services 0 36,700 K
nvcontainer.exe 9500 Console 1 21,648 K
nvcontainer.exe 9576 Console 1 31,836 K
RuntimeBroker.exe 9776 Console 1 41,376 K
Corsair.Service.DisplayAd 9816 Console 1 28,524 K
conhost.exe 9876 Console 1 5,152 K
SpeechRuntime.exe 9948 Console 1 24,268 K
svchost.exe 10120 Services 0 15,272 K
svchost.exe 10128 Services 0 8,224 K
SkypeBackgroundHost.exe 10336 Console 1 3,272 K
RemindersServer.exe 10344 Console 1 19,068 K
svchost.exe 10452 Services 0 3,748 K
SettingSyncHost.exe 10628 Console 1 5,972 K
audiodg.exe 10800 Services 0 16,584 K
LockApp.exe 10940 Console 1 48,932 K
RuntimeBroker.exe 11188 Console 1 26,348 K
svchost.exe 10656 Services 0 8,536 K
NVIDIA Web Helper.exe 11520 Console 1 7,296 K
conhost.exe 11656 Console 1 568 K
svchost.exe 12100 Services 0 7,948 K
aswidsagent.exe 3088 Services 0 39,332 K
unsecapp.exe 13304 Console 1 5,360 K
svchost.exe 12188 Services 0 4,916 K
svchost.exe 13140 Services 0 7,244 K
svchost.exe 5344 Services 0 7,548 K
nvsphelper64.exe 13492 Console 1 8,628 K
NVIDIA Share.exe 13516 Console 1 44,664 K
NVIDIA Share.exe 13656 Console 1 28,984 K
NVIDIA Share.exe 13932 Console 1 50,384 K
SkypeApp.exe 14112 Console 1 197,040 K
YourPhone.exe 14140 Console 1 8,872 K
RuntimeBroker.exe 13912 Console 1 24,212 K
RuntimeBroker.exe 14252 Console 1 5,708 K
svchost.exe 14452 Services 0 7,288 K
SkypeBridge.exe 14480 Console 1 59,988 K
SecurityHealthSystray.exe 14788 Console 1 7,044 K
SecurityHealthService.exe 14828 Services 0 12,012 K
RtkAudUService64.exe 14928 Console 1 6,696 K
AvastUI.exe 15016 Console 1 40,940 K
SteelSeriesEngine3.exe 14360 Console 1 53,176 K
RamCache.exe 5028 Console 1 19,332 K
jusched.exe 15292 Console 1 14,476 K
dllhost.exe 14552 Console 1 11,156 K
ApplicationFrameHost.exe 14992 Console 1 29,408 K
svchost.exe 15700 Services 0 6,948 K
NahimicSvc64.exe 16004 Console 1 1,240 K
NahimicSvc32.exe 16012 Console 1 1,020 K
NahimicSvc64.exe 16232 Console 1 1,192 K
NahimicSvc32.exe 16240 Console 1 4,980 K
dllhost.exe 2468 Services 0 8,524 K
svchost.exe 5944 Services 0 8,584 K
SystemSettings.exe 1604 Console 1 876 K
svchost.exe 5408 Console 1 20,392 K
ducservice.exe 1156 Services 0 20,956 K
SgrmBroker.exe 15912 Services 0 6,808 K
XtuService.exe 17252 Services 0 57,848 K
UninstallMonitor.exe 4716 Console 1 38,976 K
svchost.exe 9332 Services 0 11,832 K
svchost.exe 9052 Services 0 5,680 K
ShellExperienceHost.exe 3524 Console 1 52,968 K
RuntimeBroker.exe 7224 Console 1 16,492 K
svchost.exe 17204 Services 0 7,832 K
msiexec.exe 7812 Services 0 23,440 K
RuntimeBroker.exe 6000 Console 1 17,484 K
svchost.exe 5836 Services 0 12,296 K
svchost.exe 11572 Services 0 7,024 K
smartscreen.exe 2592 Console 1 24,736 K
chrome.exe 18380 Console 1 288,788 K
chrome.exe 19428 Console 1 10,048 K
chrome.exe 16036 Console 1 10,840 K
chrome.exe 17140 Console 1 91,764 K
chrome.exe 3924 Console 1 64,696 K
chrome.exe 14576 Console 1 69,908 K
chrome.exe 14608 Console 1 200,992 K
chrome.exe 10488 Console 1 181,548 K
chrome.exe 14772 Console 1 59,240 K
chrome.exe 4456 Console 1 46,528 K
chrome.exe 2188 Console 1 186,292 K
chrome.exe 2028 Console 1 45,432 K
chrome.exe 8308 Console 1 169,396 K
chrome.exe 9720 Console 1 51,368 K
chrome.exe 3008 Console 1 45,076 K
chrome.exe 10072 Console 1 49,444 K
chrome.exe 4540 Console 1 167,408 K
chrome.exe 1868 Console 1 133,080 K
chrome.exe 10728 Console 1 130,396 K
chrome.exe 17556 Console 1 50,996 K
chrome.exe 5172 Console 1 60,788 K
chrome.exe 7832 Console 1 50,868 K
chrome.exe 17344 Console 1 342,272 K
chrome.exe 18832 Console 1 211,180 K
chrome.exe 18744 Console 1 44,312 K
svchost.exe 18040 Services 0 19,240 K
chrome.exe 17540 Console 1 190,260 K
chrome.exe 17928 Console 1 60,380 K
chrome.exe 16860 Console 1 41,396 K
chrome.exe 18128 Console 1 45,908 K
chrome.exe 17472 Console 1 196,044 K
chrome.exe 16644 Console 1 14,268 K
chrome.exe 13172 Console 1 34,744 K
chrome.exe 7644 Console 1 33,736 K
chrome.exe 15180 Console 1 53,408 K
chrome.exe 12936 Console 1 21,180 K
backgroundTaskHost.exe 13340 Console 1 26,492 K
cmd.exe 4028 Console 1 4,192 K
conhost.exe 16392 Console 1 19,608 K
backgroundTaskHost.exe 3600 Console 1 25,948 K
tasklist.exe 5552 Console 1 12,648 K
