Well my DIY AMD Black Edition Phenom II x2 has been OK for almost a decade, but has only been up to 2 cores for almost a year, and movies and music will oddly slow down like there's a finger on the reels... Adding a SSD boot drive got me a little speed back and I'm cool with Win7 but its gonna break I can feel it.
I decided to bite the bullet and buy a ready made name brand PC, after much research I settled on the following:
HP Z2 Mini G3 Workstation
Win 10 Pro
16Gb DDR4 2133MHz 260 pin
M.2 512Gb SSD (Samsung 960, HP branded)
Quadro 620 2Gb graphics
its also tiny at 8"x 8" and can attach right to a VESA mount behind the monitor.
I found a good online deal at an HP Authorized Dealer (which gets me 3 year onsite warranty) and the company routed it all over the US to avoid CA sales tax :O bringing my total under $1k. Spendy but I seem to remember my parents shelling out $2.5k for a fresh Mac SE when I went to college (2x800k floppies, no HD!) so its relative...
It will do some games (I don't) but is really for CAD, it will run up to 6 monitors with its Displayports. I'll add a $60 USB DAC for music (FX-Audio X6) and plan to keep it another 10 yrs, its blazing fast compared to the old unit.
I still have sloooow satellite internet but just started "unlimited" data on Verizon (ie very limited!) and am running through an iPhone hotspot, which is much better.