I've been reading along with this thread because I hate to see slowdowns. It's the primary motivation I had to purchase additional Hubs and join them via HubConnnect.
I've seen "HubConnect" in a couple of messages within this thread along with the word "unlikely" - which is certainly my experience. BUT...
The ideas that are bubbling it's way to the top of my suspicions is two things... 1) the slowdowns are more than one problem. I think that the issue with C-5's and Netgear is a completely different problem than "a reboot fixes it' -- because I'm not seeing a C-4 vs C-5 distinction.. but maybe that's just wishful thinking on my part or lack of data points...
for 2) I'm seeing a lot of Cloud/Internet apps being mentioned. I know I spent a ton of time dicing up APIXU to be more 'friendly' with regards to hammering the Hub... I split the cloud connections up, made them async http, reduced the DB impact, etc. I'm more than please to see @mathew carry that across to DarkSky. But I wonder if Async Http and it's benefits haven't made it to all the most popular apps... yet. I wonder if there are loops that just pack too much into one continuous cycle. (Runs every 10 mins but the minute it does run is consuming 100%)
I know that HubConnect, will do Async Http BUT are people unaware of the Hub Impact to using http (oAuth) vs Event Socket?
EventSocket runs on your hubs 24x7 pumping out every event, as it occurs. You cannot turn it on or off because it's on all the time. If you also config MakerAPI-to-Homebridge and HubConnect-using-http (oAuth) then you've got double or triple the traffic for no benefit... or at least no outstanding (obvious) benefit.
If you can use EventSocket, it's your best solution because it is effectively 'free' -- it's running/outputing anyway - and specifically for HubConnect, there's nearly zero load on the sending Hub when using EventSocket.
For those of you using HubConnect and seeing slowdowns, please check your HubConnect configurations to use Event Socket if at all possible.
If you find you need to change, it's just a matter of selecting Event Socket on the server and copying the new key to your remote hub.
I just spent a couple of hours running packet captures of my HubConnect hubs, specifically watching for cloud traffic. I'm seeing some. It's extremely tiny.. a packet every 5 seconds average. It's hitting Amazon's AWS exclusively and I'm mentally labeling that traffic "hub checkin.' Where it's looking to see if there's a new update.
Let me be clear... I don't see the slowdowns.. I think there's a couple of reasons.. 1) I've been using EventSocket since the day Steve @srwhite wrote it. I've never gone back. 2) the cloud apps I use the most that I can edit, I've converted to async or, like APUXI, took a machete to it spread it's load across time.
At the same time, I'd just hate seeing slowdowns and am trying to see what's different for me. Remember, I saw slowdowns back in Dec-Feb of this last year/this year. It drove me to build an interconnected array of three hubs using HubLink/Link2Hub... replaced by HubConnect.
Splitting ZWave across two hubs made the most impact. Moving the Cloud apps to their own hub was a close second. Converting to HubConnect and especially/eventually EventSocket was a not insignificant benefit too. (I have a very tiny Zigbee network, and have never had a problem with it, related to slowdowns. I loath plug-in wall-wart repeaters that are necessary for Zigbee and have had too many occurrences of finding the wall-wart sitting on the floor because my kids wanted the extra socket for charging an iPad.)
I wish the same good fortune to all of you.