Hardware and Software for CAD

I must be nuts! Writing on 3 CAD blogs?
Autocad 
Revit
Sketchup

Software: 
Not such an easy question to answer, mine at the moment is swinging towards using Autocad 3D solids to model houses.   This after a brief foray into the land of Sketchup.  Revit I find wonderful and maddening in equal measure, and will probably end up going down that rabbit hole.

Common to all of these is you have to have a suitable computer to run any of them.

Hardware:
My computer is getting on a bit now (like me) and just lately has started freeze up crashes that are only fixed by disconnecting the power.

So my options are:

1. Replace the hard drive in my existing Z230 with a new SSD for around NZ$150. My wife would certainly see that one as a no-brainer. The Z230 has had it's original K2000 graphics card replaced with a P2000 Quadro, which gives life to the old girl. Using Enscape on it is a delight. but paying for Enscape, not quite so much fun.

2.Buy a new computer. Immediately there is  a choice: Workstation or PC?  A man who started work with me, suggested the following PC:
 

Item                                                                                                                                      CPU - Intel i7-8700k                                                                                                         $659.00 Arctic Silver 5 High-Density Silver AS5-3.5G Thermal Compound 3.5          $20.00   Cooler Master Hyper H411R CPU Cooler with 92mm White LED PWM Fan$44.00 Motherboard - Gigabyte Z390 I AORUS PRO WIFI ITX                                       $401.00 "Hard drive - Samsung 970 Evo M.2 (2280),NVMe SSD R/W(Max) 3,400MB/s/2,300MB/s"                                                                                                 $228.00 Memory - G.SKILL Trident Z Series 32GB (2 x 16GB) DDR4 3200Mhz CL16                $616.00 Power Supply Unit - Cooler Master MWE Gold 650W 80Plus Gold Full  Modular Power Supply                                                                                                 $162.00 Case - Cooler Master Elite 130 Ultra Compact Mini-ITX USB3.0                     $79.35 "Monitor - Philips BDM4350UC/75 43"" 4K"                                                          $885.00 Mouse - LG Wired                                                                                                           $109.00 Mouse mat                                                                                                                         $26.00 Keyboard - Mechanical (cherry brown) (PB Tech G413 Mechanical Backlit gaming-carbon)                                                                          $148.00 CD/DVD Writer  (PB Tech LG gs40N)                                                                        $54.00 Windows 10 home                                                                                                          $182.00                                                                                                                                                 $3,613.35
Apologies for the above blank space- it seems importing stuff from Excel is tricky!

2. The other option is a high spec HP Workstation, which has a supposedly better graphics card in the P4000, namely a HP Z6 G4 3FF57PA

Processor model: Intel Xeon Silver 4116RAM size: 32 GB Graphics processor: Quadro P4000 Type of chassis: MiditowerFlash/SSD

One of these is around NZ$7000, so unless you had huge amounts of highly paid work in front of you, is probably a bit on the high side. 

A friend has pointed me in the direction of some articles, which can be found on the Cadalyst site:

http://www.cadalyst.com/hardware/workstations.

Just to make things even more painful, I am still running with Autocad 2016, which may or may not run 4K nicely, should I go completely mad and get a 43" 4K monitor.  It may run, but with a bit of tweaking.