Infuriating intermittent latency on my HTPC. Hoping someone here can help...

[jluce50 118]

I'm reasonably experienced with both Windows and home networking, but this one has me stumped.

 

For the last couple months I've been experiencing some intermittent latency spikes on my Win7 Pro x64 machine. It seems to happen randomly, but I can force it to happen by browsing to a network share or initiating an RDP connection from my laptop (though this doesn't cause it every time). I'm sharing the local drive as a resource in the RDP connection, which is probably what's triggering it. Once triggered it persists for a few minutes after the activity was stopped. I'm guessing the intermittent occurrences are when the PC scans the LAN for available shares, but I can't be sure of that. This doesn't happen on any other machines on my LAN (including some Win7 Pro x64).

 

I've updated the NIC drivers (TrendNet TEW-684UB), no firewall running, and eliminated A/V as the culprit. Homegroups are disabled. I've Googled, asked on Superuser, reddit, etc. and come up with nothing. My next step is to replace the NIC, but I thought I'd ask here as a hail mary before spending the money. Does anyone know why SMB/RDP would cause latency spikes?

Edited April 16, 2015 by jluce50

[ebr 14951]

I recently had a similar problem (I think) where certain requests to the Emby server would take 20 seconds when they should only really be taking a fraction of a second.  I solved it by replacing the hard drive in the client machine.  Only thing I can figure is some sort of hardware failure on that old drive but who knows since I had to re-install everything in order to swap drives as well.

[jluce50 118]

I'm pretty sure my issue isn't related to hard drives. I suppose anything is possible, but all signs point toward some weird issue with browsing network shares.

Edited April 16, 2015 by jluce50

[Della Dog 19]

Router?

[Marc_G 92]

I've had weird latency issues also in the past. Here are some things I experienced. FWIW, I'm also on Win7x64 SP1.

 

A few months ago, I suddenly got huge latency when trying to move files around from my desktop to my HTPC, or vice versa, or even trying to stream a movie from the HTPC to the desktop. Problem was tracked down to the router configuration software on my desktop (NetGear Genie). It had updated, and the new version did something that borked my network throughput. Anytime a big network request came through, it would throttle the connection somehow. Bizarre. Removed software and all was well. Routers should be remotely managed anyway via their built in HTML page, I say now!

 

Some time previously, I noticed that file transfers and watching movies over the network was much slower than it should be. Turning off QOS in the router (and old Belkin unit) fixed that problem.

 

Before that, in my pre-SP1 days, I had issues with some network settings... I forget what it was... something about dynamic packet or buffer size? Anyway, turning that feature off on both HTPC and desktop resolved that.

 

I hope these help!

 

Good luck

Marc

[jluce50 118]

Router?

 

Yep, got one  . Seriously though, I'm not sure what you're asking. I'm pretty sure the router isn't the problem as I have other Win7 machines that don't experience any issues. 

 

For the record, I have an Asus RT-N66U running Shibby's Tomato. 

 

 

I've had weird latency issues also in the past. Here are some things I experienced. FWIW, I'm also on Win7x64 SP1.

 

A few months ago, I suddenly got huge latency when trying to move files around from my desktop to my HTPC, or vice versa, or even trying to stream a movie from the HTPC to the desktop. Problem was tracked down to the router configuration software on my desktop (NetGear Genie). It had updated, and the new version did something that borked my network throughput. Anytime a big network request came through, it would throttle the connection somehow. Bizarre. Removed software and all was well. Routers should be remotely managed anyway via their built in HTML page, I say now!

 

Some time previously, I noticed that file transfers and watching movies over the network was much slower than it should be. Turning off QOS in the router (and old Belkin unit) fixed that problem.

 

Before that, in my pre-SP1 days, I had issues with some network settings... I forget what it was... something about dynamic packet or buffer size? Anyway, turning that feature off on both HTPC and desktop resolved that.

 

I hope these help!

 

Good luck

Marc

 

 

Thanks. I don't have any router management software installed. I also don't have any issues with large transfers or high bandwidth streaming, per se. Once something triggers the issue then ANY network communication slows to a crawl. I strongly suspect that connecting to network shares is what triggers it. It could very well be some setting like you mentioned in your last point, but my google-fu has failed me in finding out what it might be...

[Marc_G 92]

Sorry about my very cryptic response. I looked into it. What helped me before was to disable the Windows TCP AutoTuning.

 

See here for more info:

 

http://www.speedguide.net/articles/windows-7-vista-2008-tweaks-2574

 

This was a while ago, but it turned very frustrating intermittent network slowness into the normal zippy gigabit Ethernet performance I expected.

 

In my case, it was probably my older router at the time, but disabling the packet size autotuning is very simple to try, and easy to undo if it isn't the source of the problem. Make sure all computers impacted have this disabled when you do your tests.

 

Marc

[jluce50 118]

Actually, I think I may have figured it out. I had created a couple shortcuts to network locations and placed them in a particular folder so they'd show up in the Network Locations section of Windows Explorer.

 

Like this:

 

One of the shortcuts was to a laptop that isn't always available. I'm guessing it was timing out trying to hit the unavailable resource. Weird that there were no log entries indicating this, but whatever. Deleting that shortcut seems to have resolved the issue, at least when I manually trigger it by opening any of the shortcuts (for some reason even opening HOME-ROUTER triggered it when the unavailable link was present). It remains to be seen if the intermittent latency has been fixed, but I'm hopeful...

Edited April 18, 2015 by jluce50

[Marc_G 92]

That's brilliant. I would never have thought of that as a possibility. I'm hoping you've cured it!

[Newalpost 5]

Last week my home network crawled to a halt.  My Mediacentre firewall raised an alert that FFmpeg was trying to access the Internet.  I allowed this through but still it crawled.  Using Taskmanager showed FFmpeg was taking a lot of bandwith on the network but once I killed the process things improve.

 

Maybe, maybe not