Issue with lots of network lag on only 1-2 clients?

Ok so before I start let me say I haven't really had any lag problems yet... before today, any time I had lag I fixed it by tweaking stuff. I've already symbolically linked my data/cache directories, set my registry up with the TCPNoDelay and TcpAckFrequency options (reduced my pings from 150 or so down to 50 when I first made this change).

Ok, so on to the problem...all day today 1-2 of my clones have had pings in the 400+ range, while my main and other 2 clones are <75ms.

Is there anything I can do about this? Seems awfully weird since they're all going through the same connection. No addons on my clones except ctmod and multiboxer v2, and thats it. The clones are so bad now that I can't even mount up on a regular mount or they lose follow :( PvP is pretty much impossible. Any advice would be appreciated, thanks!

Two things spring to mind that can cause in game latency:

Your graphics card is struggling to process all your clones and creating interface lag.... not sure if this effects the latency status though.
Second if your running all 3-4instances from a single wow dir on a single harddrive then the read times could be causing lag.....

Do you notice any lag on your network in general between your computers? Run a ping from 1machine to each and see what sort of response times your seeing as it could also be that your network card drivers are incorrect of need updating.

Anyhow check out the above report back with any findings / tests you do and well go from there :)

Well, I'm running 5 on one PC, been doing it for over a month with 0 lag. Nothing has changed about my setup, and there is no graphical lag, I can flip to any of my clones and get full FPS, its only the network latency that is affected (the green bar next to the bags is yellow on only 2 clones, and shows a ping of 400+ms whereas the main and other 2 clones show <75ms and green).

The only issue it causes is follow breaking, but its so bad to the point that I can't use a mount at all because those 2 clones (its not the same clones every time, its usually 1 or 2 random ones) will lose follow almost immediately.

Any other ideas?

Just tossing this out there, last night was fine but the day before that I had 3 disconnects and ping times from 400-3000ms. This happened two days in a row. Last night seemed to be ok. I disabled the background downloads as x5 downloading (remember these are torrents and they use your upload as well) could cause some lag. That didn't help my issue, just time did. I think they were having problems on their end doing some server work. Perhaps after a day or too it will be restored to normal like mine. Hopfully it's that simple!

Another thing comes to mind is running a spyware check, some of that stuff can really kill the bandwith.

yes i had the same problem until i turned off the blizzard patcher that was downloading future patch in background.