Build for passthrough

Hey, i’ll buy a new pc in february and this is what i’ll use it for:

1 - Programming (webdev/data science)
2 - Games (passthrough)
3 - VMs (infosec)

My nº1 priority is successfully passing through the VGA for a windows box, i’ve been using linux for roughly a year and a half and XCOM 2 gets boring after the 100th run.
2º would be budget. This is not a budget build per se, but i’m trying to “run 1080/1440p games on ultra for as long as possible for as little as possible”, which is why i picked gtx 1080 over 1070, i imagine 1080 will last for half a generation longer than the 1070. If i have to spend a little more money, it’s ok, but that implies more time playing xcom 2 over and over, which i would like to avoid.

Here’s the build:
host VGA: GTX 760
guest VGA: GTX 1080
CPU: Ryzen 1600x (Really considering the 1800x for VMs, the price difference is negligible for some reason)
RAM: Corsair Vengeance LPX 16GB 3000Mhz
Power supply: EVGA 650W gold.

Mobo: Often times i see x370 mobos being used for passthrough, are they that much better (or is the asus prime that much worse)? I’m not from the US and the price difference can get quite high when compared to the asus b350, around 400 bucks or more depending on model.
I don’t want to risk end up with a computer that i can’t passthrough successfully, as i’ve never done this before, so i would certainly pay the price difference if necessary.

Host VGA: Doesn’t worry me that much, it’s quite old and will probably need replacing soon, but that doesn’t seem to be an issue for VFIO (i’m aware ryzen CPUs don’t have built in cards but i can probably find used cards for pretty cheap).

Guest VGA: I was between 1070TI and 1080, but the price is equivalent enough not to be an issue. My only question would be whether i should buy a radeon model, considering error 43 with nvidia GPUs. Is it any smoother to passthrough using radeon models?

CPU: The only reason i’ve listed 1600x is because the price is almost equal to 1600. But the ryzen 1700 is at the same price too for some reason, would more cores make passthrough smoother? Even a 1800x would be within budget, surprisingly enough.

VFIO: If i were to buy another KVM, would i be able to run linux in one screen with chats, work, internet browsing, and games in another screen, with another set of keyboard and mouse? Ideally not ever having to deal with anything other than gaming on my windows box (if, during gaming, my linux host is locked, i’d probably have to send messages on my windows box for example, which is undesirable).
I heard about audio problems when on the guest VM, do i have to buy an audio card for the guest? If so, can i just buy any cheap card?
Also, since @wendell’s last video, has there been any change in the passthrough proccess? Because my idea is following that 1:1.

Are there reports of this board working? What you need to check is if the m.2 breaks out into a pcie slot. If not, passthrough won’t work. It’s sub-optimal on B350 because, at best, you get a pcie 3.0x4 connection to your second graphics card. The same pcie 3.0x4 lanes normally used for m.2 in fact.

The asrock AB350 k4 I think does this – @gnif uses this board iirc, but at pcie x4, which may be a bottleneck with your 1080. an x370 in general would at least give you x8/x8 pcie 3.0 splitting which is something.

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I’ve seen a thread in VFIO’s subreddit with this mobo, but it wasn’t a smooth passthrough apparently. I’ve also found another person who made it work, but had similar problems, but can’t find the thread now.

I’m looking to buy the x370 taichi, but currently it’s sold out. x370 being unavailable, are there any other mobos that you would recommend?

You might wait for the 400 series chips? Other than that check for the m.2 pcie lanes in a second slot and know you will be running at x4, at best, no matter what you do on b350


The Taichi is a wonderful board, but I would wait on the 400 series chips, especially if you’re considering zen+. Also, I’m not sure that Wendell covered this, but the extra cores will absolutely make a difference in passthrough. If you can afford a 1700 (or zen+ equivalent), go for it. It’s what I have and I’m happy with it, running at 3.8GHz on the wraith spire cooler. (could push further, but would like to get better cooling before I do so)


Hmm, i’m not sure if i can wait for the 400 series to come out, i’m not from the US so even if they come out before february or march, i’ll still have to wait for them to be sold in Brazil, which can take a few months.

I’m currently between MSI ATX X370 SLI PLUS, and the x370 taichi. Ideally i will get the taichi, but i can’t find it in any store so hopefully they’ll re-stock by february.

Ah, that makes sense.

I don’t have any experience with the MSI. I can tell you, though, that the Taichi is amazing.

Have you tried shipping from another country? That’s probably prohibitively expensive though.

Yep, shipping from another country is way too expensive. MSI does seem to be a little problematic, but i think by february the taichi will be restocked. I’m considering the 1800x now too, since the price difference is negligible for some reason (seriously, it’s almost the same price as 1600, i have no idea why).

If the price between the 1700 and the 1800x isn’t much, I’d jump on the 1800x. It’s a higher binned CPU.

It’s probably sinking because no one is buying them. I had the budget for the 1800x, but got the 1700 because I just didn’t see the benefit of paying $150ish more for something that can get about 0.2GHz faster (maybe) than the base-binned chips.

Supply and Demand. :smiley:

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Sorry for bumping this thread but i just bought a power supply and i may have fucked shit up. My GTX 760 needs 2 6-pin connectors, the gtx 1080 needs 1 8 pin connector. I should buy a modular power supply right? The closest i could find for something that might work is a power supply with 4 pci-e connectors, but modularity might be more important in this case.

tl;dr: is a modular power supply necessary for a gtx 1080 and gtx 760? Considering gtx 760 uses 2 6-pin and 1080 1 8pin.

It’s your thread. Bump it all you want.

Also, it’s not gravedigging until 30 days have passed. Typically though, a thread can be bumped any time with certain exceptions. (ex: a help thread where OP continues to have issues)

Not really. If you have unused cables running from the power supply, the cables can just be coiled up somewhere. A modular supply is nice for neatness factor, but having a non-modular isn’t going to have negative effects.

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I just found a MSI x370 SLI plus on sale for almost half the price, i watched wendell’s review and since it’s from march i imagine the IOMMU problem is solved. I couldn’t find anyone who successfully passed through using this board tho, so i thought i’d ask before buying. What do you guys think? Is it worth it to buy this over the taichi considering i’ll be paying almost half the price?

I don’t know if this was fixed. I did a bit of searching and found this thread, not much help though.

@wendell, have you played with the MSI x370 SLI since the UEFI updates have started fixing IOMMU groupings?

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Iommu groupings are fixed on latest uefi. The sli plus has been a champ for me the last few months in testing.


Thanks a lot, one last question, do you know if the corsair lpx CMK16GX4M2B3000C15W is compatible with the sli plus? The CMK16GX4M2B3000C15 (without the w at the end) is in their list of supported DIMMs, i imagine this model would also be similarly supported, right?

It’s hard to can’t count on even very close model numbers meaning much. Probably? Make sure the 3 timing numbers are the same. That often, but not always, indicates Samsung memory. E.g. 14-14-14 or 16-16-16

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Yeah, everything checks out, i’m pretty sure the W refers to color, the memory i’m buying is white (W at the end), if i pick a red one the last letter is R. Removing the last letter (that probably refers to color) the model is in the list. Thanks a lot for all your help! When i finish buying and doing the passthrough i’ll try to write a step by step guide, might help someone else.

good point. probably correct, just been burned by “gee thats awfully similar surely it will work” in the past. Ryzen is not as tempermental as it was when it launched, so this is probably fine then.

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Yeah i would recommend to grab a X370 board aswell.
Because B350 boards arent really that great in quality yet.
But also the pci-e lane configuration layout on “most” B350 isnt really that ideal either like @wendell also mentioned.

  • Asrock X370 Taichi
  • Gigabyte Aorus X370 Gaming K7
  • Gigabyte Aorus X370 Gaming 5.
  • Asus X370 prime pro.

Those should basiclly work with the latest UEFI updates and patches.

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I would recommend getting a radeon card to passthrough. The NVIDIA cards give you a code 43 error:

Although this error is easy to fix. It shows that nvidia is deliberately hindering customers that use pci passthrough. Personally, Im willing to pay a little more for a graphics card that allows me to do whatever I want. However, with the fix shown on the archwiki, getting the nvidia card to work should not be a problem for now.

With my RX 580, the install was plug and play. The amd drivers installed and just worked in my virtual machine.