1 PC, 2 gamers

[MrDadosz]

Hello. I'm going to make a "one pc 2 gamers" like Linus did and I have a couple of questions.

 

My current specs:
GPU: Asus RX 470 4 GB (undervolted to 1025mV)
CPU and heatsink: i5-6500 with SilentiumPC Fera v3, AM4 compatible
RAM: HyperX 2x8 GB RAM DDR4 2133MHz
MOBO: MSI H110m Pro-D
PSU: SilentiumPC Vero L1 600W
2 monitors: 1920x1080 (DisplayPort, 75Hz) and 1680x1050 (HDMI from GPU to DVI monitor)
Case: SilentiumPC Regnum RG1
Disks: 1x Seagate 1TB 7200RPM, 1x old Hitachi 250GB from laptop, 1x 750GB 5400RPM disk from laptop

 

...and sell mobo, cpu and stock cooler

 

What I want to do:
GPU1: Asus RX 470 4 GB + undervolt after GPU pass-through
GPU2: 1050ti or 1060 + undervolt after GPU pass-through
CPU: Ryzen 7 1800x with SilentiumPC Fera v3 from old PC - I think i7-8700k hasn't enough cores for this
RAM: HyperX 2x8 GB RAM DDR4 2133MHz + 1/2x8 GB RAM DDR4 3200MHz
MOBO: MSI X370 Gaming Plus

(?) or Gigabyte GA-AX370-Gaming K5(?) 
Same PSU, that should hold this PC without OC.
+1 Full HD 75Hz monitor
Same case
Maybe one SSD for host (?)

 

I'll use that PC with my sister - we don't have space for second PC, even for ITX case (and I don't want to spend more money for buying low profile GPU's). I'm playing some games like Fallout 4, Witcher 3 or GTA 5, my sister wants to play some new games either but I don't think that I want to buy better GPU's - I used that RX and it worked fine for two games, CPU had problems (I used IBIK aster software).
I want to make one PC with Linux as host and two VM Windows 10. 2 GB RAM for host, rest for two VM. 1 core for host, 3 and 4 cores for 2 VM.
What about performance and 24 PCI-E lanes with these GPU's? Will it have same performance like my current i5-6500?
What about dual channel? Is it working  separately when I put 2133 in 1 and 3 slot + 3200 in 2 and 4?
What about splitting USB devices and audio?
Wait for new Ryzen or buy 1800x? 
What do you think about this?

[Mira Yurizaki]

I feel like for the amount of money you would have to spend, you could've just built two decent PCs and save yourself the headache of having to set something up.

[MrDadosz]

Yes, but the other computer would stand in the middle of the room or hang on the wall... That would cost 1400(CPU)+470(Mobo)+350(8GB of RAM)+700(used 1050ti)-600 for selling my current components = 2320zł ~= 677$

without monitor. New PC with i3-8100 would cost 455(CPU)+450(mobo)+350(8GB of RAM)+200(psu)+700(gpu)+150(case)+100(better cooler, stock is too noisy) = 2405zł ~= 702$

Almost same price for new PC. What performance would be with Ryzen, better than two different PC's or worse? 3 cores, 6 threads for first VM and 4 cores, 6 threads for second VM.

[aezakmi]

it'd be more expensive than just getting another computer and perform horrible, not to mention the drivers conflict because of the radeon + nvidia thing, and the ram? only 2133, it's not like you can make it work at 2133 on just a slot and at 3200 in a different slot using the same mobo, it doesn't works that way

[MrDadosz]

Yes, my bad. RAM clocks would drop to 2133MHz.

I thought I have to buy different card to pass-through it to virtual machine because same models would have the same IOMMU group.

I saw that performance compared with normal system is around 95% so I thought that would work.