Blender seems to be broken.....

2.8...2.81...2.82 , every time I seem to install a newer version of Blender , it seems to go slower and slower for me. 

I have a pretty decent setup : 4 x 1080GTX Ti GPU's , i7 processor , 64GB RAM , SSD drives , but ever since the release of 2.8 , I am experiencing some very sluggish , and weird behaviour that isn't typical for a PC like this.

For example today , I am rendering out tests of a very simple scene I have built : 

With the SubD , this lettering is 219000 tris with a single sun lamp and a 4k material texture. There is nothing else in the scene. Yet whilst viewport rendering in cycles , it is painfully slow. It takes a good minute to initialise , and then EVERY change I make , no matter how small , such as simply changing the strength of a light , or its colour results in a re-initialisation of around 30 seconds before it will render. And in the node editor , simply clicking a node just to select it makes cycles feel the need to re-initialise and make me wait 30 seconds before it re-renders. selecting objects in the scene , moving a node , clicking almost anything will make it do this and it is so frustrating especially when you aren't even changing anything in the render. 

I'm sure back in 2.79 , you could change a lights brightness , or colour in real-time and it  would update it in the viewport? Have I got some setting in the preferences wrong , or is this typical behaviour for 2.8 and onwards?

Also with sculpting - Back in 2.79 my computer could handle sculpts of 5 to 10 million without any sign of lag. Now , a scene with anything upwards of about 3 million verts takes an age just to switch modes and sculpting is impossibly laggy. 

UNDO - this now takes around 30 seconds to undo a single step on any scene that is over a million verts. The same goes for switching to edit mode , saving , loading - all things that my PC could do in a split second on any vert heavy scene. 

Animation playback - The other day , even with simplify on and certain objects hidden , a character idle cycle was running at 8FPS even in wire-frame and the character was the only object in the scene.    

Also worth mentioning - I have also completely lost the ability to split viewports , When I hover around any of the buttons in the bottom left of a viewport, I don't get the cross-hairs that I used to and there is no way to split it. Could this be a bug I should report or has the way to split views changed now? 

If its any help , I have completely wiped my PC , rebooted it and installed all the latest drivers , and I have plenty of free space on my SDD's. 

Is anybody else experiencing this kind of behaviour?

Thanks for any help and advice :)