[sebazzz]

I also have a very odd issue which I think has its root in the underlying firmware. I have an Dell Latitude E6520 notebook with a Intel Core i7 Sandy Bridge processor. Though I bought this laptop in 2013, it is still fast and works quite well even with Visual Studio / ReSharper.

Only one thing, it is sluggish as hell. Mouse clicks not responding, everything feels slow. Except when I undock it from the docking station and redock it again. Then you feel the fan spinning up, the CPU doing work, and everything becomes smooth. I checked the clock speed, its the same before and after docking. There is nothing keeping the CPU busy either. Its like something is somehow preventing the system from executing efficiently until the system is re-docked.

The solution? I don't know, I might never find out. I will just keep redocking my laptop every time I boot Windows.

[goldcd]

Your real problem is that you have a known workaround - you'll maybe some time trying to work out the issue 'next weekend or the one after', when you've got a bit of free time :)

If you can find a bit of time - CPUID & HWMonitor are handy tools for just capturing what your CPU and motherboard are currently up to (compare when slow and when fast)

[beachy]

I think yours is a pragmatic attitude in this age of interconnected complex technologies. Debugging things is satisfying but time sucking.

My eclipse on fedora has a hideously annoying flashing effect while editing e.g HTML files. Seems to be caused by the top menu disappearing and then appearing again a second later. The janky effect is infuriating, but at the same time, half an hour or so of googling has led to nothing, and I can sense a rabbit hole of frustration if I try and get to the bottom of it.

The most pragmatic approach feels to be too just put up with it until something else happens - perhaps a shift to Ubuntu so that I can screen share again will resolve it.

[jotm]

In my experience, the GPU, USB and SATA are the causes of sluggishness without CPU usage. Not sure what could be the problem with your dock - does it have a USB 3.0 controller that the laptop does not? eSata? You are 100% sure the CPU is not being heavily used by anything after first time docking?

[sebazzz]

The dock is a standard wide-connector Dell port replicator, with indeed USB, DVI connections and possibly eSATA. USB 3.0 did not exist back then.

[PascLeRasc]

It sounds like you have a slow HDD in there, an SSD would certainly help with sluggishness. I'd also recommend repasting the cooler with Thermal Grizzly paste, it's sub-$10 for enough to do 3 CPUs and it's the best non-conductive paste available.

[sebazzz]

So after redocking my HDD is suddenly fast? No, I don't think so. It is an SSD BTW, I also have a secondary HDD.

[amaccuish]

Maybe the fans aren't running when they should and the CPU is struggling with heat?

[Klathmon]

Won't Intel chips down clock in that case?

[billforsternz]

I think that's the point.

[Klathmon]

The parent commenter specifically said they checked clockspeed was good.

[billforsternz]

Good point, I missed that.

[free652]

I have a feeling you that you got a Nvidia card, so disable Optimus in bios.

[sebazzz]

Yes, that is disabled.