One of the biggest bug-bears on Windows Phone in recent times, for me, has been the performance of Skype, especially in light of the emphasis on the application in hardware launches, e.g. for the Lumia 730/735 here. The issue is that, when returning to Skype on anything but the newer 2014 Windows Phones, even if we only just let the screen timeout and unlock it again, or even if we use the multitasking carousel, we still see completely unnecessary 'resuming....' dots, as shown in the video below.

First, some video proof. This shows the high end Lumia 1520 and the low end 630, both with 'modern' Snapdragon chipsets and hardware 'families', plus the Lumia 1020 and 920, both with the older Snapdragon S4 powering things, all running Windows Phone 8.1. Why do I mention the processors? You'll see.

Having started up each phone from scratch and then loaded up Skype, I then:

1. switched away to the Windows Phone Store
2. locked the screen
3. unlocked it again
4. used the multitasking carousel to switch back (resume) Skype.

In the latter case, I do it a pair of devices at a time, for clarity and practicality reasons.

Notice the difference? It seems that Skype resumes immediately and perfectly on any device with a 2014 chipset and skips back into having to effectively reload from scratch on anything older. In the video above, the delay was only a couple of seconds every time, but I've seen delays as long as 10 seconds in cases where Skype hadn't been used for a few hours, on my 920 and 1020.

The very fact that Microsoft is promoting Skype as a hero function in new device launches, lead me to suspect that the company isn't testing it on enough handsets. A phenomenon through the whole computing world since the dawn of time is that programmers tend to code and test on cutting edge monster PCs and then wonder why regular users with far less capable gear complain about application speed. The same seems to be happening here - it's clear that the Skype coders at Microsoft are testing on the 1520, Icon, 930, and the brand new 730 and 830 prototypes. Even the new low end 630. But I doubt whether any of them have tried using Skype recently on a Snapdragon S4-powered Lumia from 2013, otherwise this issue would have surely been picked up sooner in every day, real world use.

I'd love one of the Skype team to get back to us with an official comment. Is there a technical reason why Windows Phone applications can't resume in quite the same way under the Snapdragon S4 and its hardware family? Comments welcome if you can shed any light on this.

In the meantime, those of us struggling along with Skype on a Lumia 1020, 920, 925, 820, 720, 620 or 520 (etc. - so the vast majority of the Windows Phone installed base) will just have to wait. Multiple times a day.

... Resuming... ... ...

PS. Are there any other Windows Phone applications which you find almost as frustrating in terms of resumption speed? I'd hazard a guess that Twitter might be a candidate too?