About a month or two ago my main PC (also HTPC) started having some intermittent latency issues.
PC:
- Win7 Pro 64
- TRENDnet Wireless N 450Mbps USB adapter (TEW-684UB) - connected at 2.4Ghz
- SABnzbd
- uTorrent
- Pulseway service
- Dropbox
- Carbonite backup
- ESET Nod32
- Malwarebytes Anti-Exploit
- Windows Firewall disabled
... and more
Router:
- Asus RT-N66U running Tomato Shibby v121 K26AC AIO-64K
- 2.4Ghz @ 40Mhz channel width
- 5Ghz @ 20Mhz channel width
- WPA2
Now I've all but eliminated the router and the wireless connection as the problem. The PC is quite close to the router and inSSIDer shows a very strong connection. I'm reasonably confident that the issue is on the PC. Both SABnzbd and uTorrent are always running, but only occasionally downloading. Their activity doesn't seem to correspond to the problem. I've disabled and even uninstalled the AV to no avail.
Basically, what happens is that the latency will randomly spike way up (~1000ms) and stay that way for a while, then come back down to normal. None of my other LAN clients experience any issues whatsoever. One way to reliably trigger this is to connect to the PC via RDP with the Performance setting set to "LAN". Even after disconnecting the latency will remain high for a while. This isn't necessary to trigger the problem, though.
I'm at a bit of a loss as to how to troubleshoot this. I've updated the NIC driver. I've looked at active connections using Resource Monitor and didn't see anything out of the ordinary. Is there some other piece of software that might help? Perhaps something to look at all TCP connections to see if it's being flooded or something? Any other ideas?