Help with part selection (ryzen, linux, kvm, blender, games) please

Hardware Hub Build a PC
1

i’d like to keep my budget to about $1000 US max. this isn’t likely to be a machine i replace in two years.
i’m likely to upgrade some parts to extend it’s life rather than replace it entirely until i feel the cpu is so out of date that it’s keeping me from doing some stuff i’d like to. case in point my current cpu is a fx-4100 that i got in early 2012 and i’m just now looking into upgrades.

i generally use linux in most cases and my main focus for this comp is as a blender machine.
i do play games on occasion (most of them in linux) as well as have to use windows for when i occasionally work from home (autocad).

i find i’m happy with the gaming performance of the rx480 i have.
it’s not the fastest thing for blender’s cycles engine but since i’ll be using blender’s eevee rendering when version 2.8 finally gets here buying with cycles in mind seems to have an approaching expiration date. so for gpu’s i’m generally more interested in vram rather than core count/maximum horse power.

as mentioned in the title i am interested in running windows in a KVM rather than dual booting.
rebooting when i have to do something in windows is a bit of a pain but actually installing winderz on a ssd might make it more bearable.
i find that if i have to boot into windows to play a game i tend not to actually finish that game even if i enjoy it. there’s also the matter that i need the proprietary graphics drivers for blender in linux but i’ve seen a number of posts in various places mention that the performance is better with the open source drivers so being able to use a KVM for gaming rather than dual booting seems like it’d be a good solution there.

i’ve been strolling through the forums and some other places and this is where i’ve ended up at.
https://pcpartpicker.com/user/daedalJS/saved/#view=MjGsYJ

any input is much appreciated.
also note that while the pcpartpicker list shows two rx 580’s i actually plan on using the rx 480 i’ve already got for one of my cards. anyone know if i can use a 480 and a 580 or should i grab a nvidia card for passthrough instead?

2
3

thanks for that.
i’m not sure how it’s supposed to help me though. after all, i do know how to do basic addition, have a general understanding of how to put a computer together (i have put together several), and my intended purchase isn’t just for a standard money to performance scenario as my wall of text up there explained.

also, i’m not sure how it’s helpful to spend more money on a case as my budget increases, as the site suggests, when i can find a more budget case to suit my needs and wants just fine.

for now the areas i really need help in would be:
what’s a good mobo for Ryzen on linux that’s also not really gonna give me problems with KVM and QEMU?
should i be buying ECC memory? does that matter? would there be a better option for RAM choice than what i picked even though it was listed as compatible on the MOBO’s list?
also, what are some of the hardware specifics for GPU options with IOMMU passthrough when one of my cards is going to be my current RX 480? will a 580 or 570 work well in that situation with an rx 480?