Building a new system for VM(s) with GPU passthrough

Hi all, so in the last couple of weeks I’ve made a couple of important discoveries:

  1. Wendell and well, this site!

  2. How much telemetry is still enabled in Win10

So time time to move away from Windows as a daily driver finally and fully shift to Linux, except for gaming. Also, time to upgrade my tired old FX-8120, so my GTX1070 finally has a CPU that can keep up!

I’m toying with a Ryzen 2700X or an Intel 7820X. The Intel system is $400 more expensive in Australian rupees.

I would describe my knowledge of Linux as fair and may need a bit of time to get everything working the way I want, but, I don’t mind dealing with a suboptimal system for a while as I learn things. However, if the Intel system is just straight up, going to be significantly easier to setup, use, for compatibility etc. then than is a valid argument.

Any thoughts from all?

Regards
Mick

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I’m in the same situation and settled on a 2700x a couple of weeks ago.

Better bang for buck. I’m going to do this with Fedora 28

So far, fedora 28 installed easier than windows. The 2700x seems to be a great CPU so far.

That said, that’s as far as I am along just yet.

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Thanks @thro! Glad to hear your Fedora install went well, that’s positive news, although I’m probably going to go with Ubuntu (at least to start.) Are you planning to use GPU pass-through at all? If so are you running a second graphics card?

Yeah I’m really leaning towards the 2700x, after having a looking at this review (linked elsewhere on this hardware forum)

It seems to tick all the boxes.

Intel did throw a spanner in the works with the rumour of a 8-core coffee lake CPU bound for this fall though. I had originally discounted coffee lake to only 6-cores (with HT) and I plan to dedicate 2 to the host. This left only 4-cores (with HT) for the VM, which although probably OK for now, I think the days of 4-core gaming are finally just about done. It’s just hard to go past that per-core performance boost and the iGPU for the host.

So I’m toying with the idea of going coffee lake with a CPU I plan to bounce on EBAY after 6 months, I’ll take a $100 loss or so, but, I can probably live with that (if I can find a used coffee lake, Ill grab that.)

Any thoughts?

Yup, i’m planning to use GPU-passthrough.

I have 2x reference Vega 64s, so i’m going to have the additional complexities of

  • identical GPUs for host and guest
  • possible AMD GPU reset issues for the VM (i’m hoping this will be fixed or i can work around it

If you’re looking to do GPU passthrough i’d suggest Fedora - its a lot more bleeding edge than Ubuntu and there seems to be more documentation/GPU-passthrough users running it.

I’ve not been home a lot lately, have just been making sure the system is stable on the memory timings, etc. i have before i go trying to make things more complicated just yet :slight_smile:

Re: coffee lake 8 core… motherboards are more expensive, CPUs are more expensive. The 2700X stock cooler is good (intel? haha, if you get one, it’s crap). AM4 is supposedly supported for 5 years, so IMHO its a no brainer. You can get an 8 core ryzen TODAY. If you need more cores than that, consider Threadripper.

I’ve been very happy with the switch the AM4 so far, my last box was a haswell system, i’d been intel for the past 20 years before this.

I very nearly went threadripper myself, however it was for memory and PCIe lanes, but my old machine died and the 1900X was out of stock locally. Stepping from 2700x to 1920x was a pretty big jump in price (and if you’re going that far may as well just go 1950x) and realistically just don’t “need” it for my use.

edit:
the other thing i’m going to try and get working is to do multi-player gaming via this set up. Girlfriend via steam link via the Windows gpu-passthrough VM, myself under Linux. 1x Vega, 4 cores/8 threads and 16 GB of RAM each. :smiley:

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Thanks @thro, yeah I’m probably too hung up on the old IPC comparison. Both your points are good and valid, on price and availability for the Ryzen CPU. Mainly I was worried about support for Ryzen under Linux vs Intel, but, the more I read it looks like there’s no big issues either way, only quirks.

Fedora hey, well it’s been a while since I played with that distro, but one of the goals for the new build is to immerse myself more in Linux, so happy to give it a shot. I’m going to have multiple VMs anyway for the single GPU pass-through, so might as well play with differing distros too! If it doesn’t prove to be too much of a pain that is, in which case, it will be a cheap GPU to the rescue.

Agreed, Threadripper is tempting for the lanes and memory and I was originally looking at it for that reason. But, in the end, like you, I don’t really need the features for the workload I have in mind.

Good luck with the identical GPUS :slight_smile: I get the feeling there might be some board swapping and a couple of “Oh, it’s that one(s)” happening in your near future :smiley: (once you’re happy with stability anyway.)

If you have a chance once you get the multiplayer gaming happening, post it! I’d be very interested.

IMHO the IPC comparison is dubious at best - its only really relevant at low-res gaming with overpowered GPUs (which people just don’t do). I don’t personally agree with that as representative of “future CPU bottleneck” performance testing.

IMHO as new APIs like DX12 and Vulkan become more important it will be less relevant, and more cores will be more useful. Also more CPU power (in terms of core count) will be required by the game engine as time moves forward. i.e., by the time 1080Tis, etc. are pushed - the CPU requirements will be different and likely no longer single thread focused.

Also, anything on socket 2066 with the mesh bus (e.g., i7-7820x) has similar disadvantages in terms of IPC to the AMD parts anyway. Sure they clock a little higher, but… not like 8700k clock speed…

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Yeah I’m starting to agree with your statement on IPC, I think that most of the performance discrepancy is more to do with application optimisation (particularly games.) Developers simply haven’t needed to worry about AMD for so long, it’s taking a while for coding to be embedded to support AMD specific features that improve performance, particularly the higher core/thread counts.

I do play at 1080p, where an Intel focused build could potentially perform better, however, until I upgrade my monitor I’m locked to 60fps anyway, so that’s probably a moot argument. Even then when I upgrade, I think it’s pretty likely I’d be moving to 1440p as well. Which on a 1070, makes the GPU the determining factor in setting the fps I’d reckon.

Funnily enough, I noticed a huge improvement on my FX-8120 when I switched DX12 on with Rise of the Tombraider. I was actually pretty impressed with how well that game ran (in scenes where there wasn’t too much happening at least.) It was nice to finally see all those cores running hard, instead of the usual single 100% pegged core. Can’t wait to see how that will look on Ryzen.

Very good point on the 2066 socket, I hadn’t considered the mesh bus factor. AND I’ve decided I’m not going to wait on the 8-core coffee lake (8800K? 8900K? whatever :slight_smile: ) I’ll post a build list once I’ve 100% decided on my budget.

Probably this:

I’ll add this to my existing Corsair 570X case, GTX1070, Samsung SATA 850 EVO SSD and Seagate 3Tb data drive.

I’m undecided on the RX550, it’s there to hopefully make my life easier dedicated to the host, with the 1070 in the Win10 VM. Also, ideally if Looking Glass KVMFR can get AMD freesync to work, it might change my future monitor choice.