One of the most common questions we get is: “how should I build a VFIO PC?”
Admittedly, this is a pretty hard question to answer, which is why we created this page. This table contains a coherent list of parts for VFIO-focused builds at different price ranges. The FAQ section below includes information on the rationale in choosing these parts, as well as workarounds you’ll need to do depending on what you choose to buy (components that need workarounds are signposted with asterisks.)
We constructed it in the hopes that it becomes a go-to reference for the passthrough community. It takes a lot of time and effort to maintain, so if you like the fact that we keep it up to date, consider supporting us on Patreon.
ADVISORY: Basic Ryzen platforms have been removed from the increments chart because of a bug affecting UEFIs on AGESA 0.0.7.2 and later that completely breaks VFIO functionality, and prevents the user from downgrading. They will be Re-added as soon as this issue is resolved. AMD GPUs increasingly carry the Reset Bug, and will only be added if we can validate a specific model across multiple guest VMs.
Mostly, yes. However, OS X has much stricter requirements when it comes to Guest GPUs. You want to go with a 700 Series Nvidia card or an AMD card instead of the nvidia devices listed on the chart for best compatibility
This is because all future versions of OS X will lack driver support for new nvidia cards. Kepler is the last universally supported Architecture and 700 Series cards are the only ones that universally ship with UEFI boot support. Note also that the GT 745, 750 and 750 Ti won’t work because they’re rebranded maxwell devices. On the AMD side, anything older than Hawaii (R9 290/390) Will be reset bug free, but some polaris (RX 400 and 500) cards will also work. Vega and Fiji (Fury/Vega) cards seem most susceptible to the reset bug, so avoid those if possible.
Long story short, the vast majority of laptops don’t support passthrough, and even the ones that do make it incredibly painful to set up. Even then, not all guest operating systems will work, even if you can get it working for one of them.
There are 2 methodologies for enabling passthrough in Laptops:
Older laptops (or newer models that don’t have bios whitelisting) can attach a desktop GPU via the mPCIe or m.2 slot normally reserved for a wireless adapter or NVMe drive using a variety of adapters. These don’t typically give the full bandwidth needed for 100% baremetal performance but they’re the most compatible with traditional passthrough methods. Laptops that support expresscard or pcmcia also have this option available, but are usually too old to be relevant.
Thunderbolt laptops also have tentative support for this, but it varies by model.
This category of passthrough is a lot more dependent on your laptop’s native hardware configuration. Older models with MXM based GPUs can work, but newer “optimus” models depend entirely on the implementation of their intel/nvidia GPU muxing. If your bios does not support manual override of one GPU or the other, chances are it won’t work. If it does, and you have physical ports dedicated to the discrete gpu only, then you may be good to go with some extensive tweaking, but there’s no guarantees.
Search https://www.reddit.com/r/vfio with your Laptop’s model to find specifics.
Most likely due to compatibility or quality control reasons. For some components, we just try to find the best price without venturing into unreliable territory, for others, it’s more complicated. We’ve listed reasons for popular ones below:
The most recent releases from asus have had underwhelming build quality, and on AMD platforms, an issue with their UEFI tanks performance in VMs if you try to tweak certain power management settings. Their inclusion will change if these factors change.
Higher year over year failure rates and price per GB than other brands.
If your PSU isn’t from an ODM you have no way of telling how reputable the designer actually was. We feel that it’s worth the peace of mind to go with ODM brands if it means spending a little more.
AIO Water Coolers
Put simply, the cost and failure risk associated with these devices makes them hard to recommend. Most AIO systems, even ones somewhat more expensive than top end air coolers, perform the same as, or worse than air cooling, while introducing a lot of negatives. Custom water loops offer a real advantage because they typically have much more fluid (and therefore thermal capacity) as well as far more powerful pumps than your typical AIO water system. They also allow you to cool your GPUs more effectively while using them in a single slot configuration. You take away those advantages when you move into the AIO segment of products.
[INSERT CASE MANUFACTURER]
We prioritize airflow and construction quality over adolescent aesthetics and LED lighting when choosing cases for this page. If you need RGB, tempered glass, and restricted airflow because of the first two in your life, feel free to use a different case provided that it clears your chosen cooling solution
A PSU can make, or quite literally, break your system. As such, we only list PSUs that come direct from reputable ODMs in the industry, with good track records in the enterprise market.
Sometimes you can find a better deal on a PSU via resellers or OEM rebrands. However, reseller brands (corsair, EVGA, etc.) release revisions and products in the same series from less reputable Shenzen designers, and navigating the details of this market can be a lot of trouble.
If you can find them, Seasonic, Super Flower, FSP, Channel Well, and Delta are the brands to look for.
It’s an HDD. Cheap, spins, keeps your data safe. You should have a few in your system unless you need absolutely silent computing for your recording studio, in which case I’m not sure why you’re here.
We like to recommend Toshiba and Hitachi HDDs over Seagate and WD, because the numbers from several wide spectrum evaluations put them at the lowest failure rates year over year (other than HGST, a subdivision of Hitachi that was bought out by WD recently) and they’re also consistently cheaper per GB. We periodically update listings with best price/GB drives in the table above, so be sure to check back every once in a while if you’re looking for a bargain.
There’s not a whole lot to say about RAM.
Intel platforms will pretty much take whatever you slot in, and the amount you can pass to your VM is the only relevant metric to passthrough gaming.
AMD platforms will need to be vetted according to your motherboard’s compatibility list, and Samsung B-Die kits will generally perform better. Ryzen does scale a bit more dramatically with increased frequency due to the way it’s memory subsystem and CCX interconnects work, but as long as it’s listed as compatible you shouldn’t run into any issues. Generally, you want to buy the cheapest sticks you can find from a reputable brand.
[***] B-Die isn’t magic, it just tends to be more compatible with AMD platforms.
This is the card that your host machine will use when your Gaming VM is up and running. Platforms with iGPUs don’t need an additional card, but Intel HEDT and AMD platforms will. If you need to drive a lot of monitors, do creative work, or want to game on your host in addition to your VM, feel free to get a higher powered card. We’ve chosen the GT 710 as a catch-all Host GPU because it can drive multiple monitors, and only costs around $40 USD.
Note: choosing the same model of card, or in some circumstances, even the same manufacturer as you use on your guest VM can cause problems. A good rule of thumb is to go with AMD on the host if you use Nvidia on your Gaming VM, and vice versa. While not 100% necessary, this will avoid complicated vfio-pci and modprobe configurations.
One of the most important parts of your build will be the guest GPU, and selecting one with high compatibility that fits your needs can be difficult. Here’s a quick rundown on what to look for.
What’s a Guest GPU?
It’s the graphics card that you pass over to your virtual machine to enable 3D acceleration and Gaming. Ideally you would be able to share it between the host and guest, but we don’t live in a perfect world, so you (with a few new and very expensive exceptions) need two GPUs, one for each OS. On systems with an iGPU, this means you only need to buy one discreet card, but on AMD and intel HEDT platforms, you’ll need a Host card as well.
Miners will buy up a lot of models as soon as they hit the shelves, so even highly compatible models tend to be scarce at a certain level of performance. Generally, though, there are 2 routes you can take for effectively selecting a Guest GPU:
Nvidia — all the cards are “broken”
Luckily, they’re all broken in the same way. Nvidia’s drivers will abort with an error if you try loading them in a VM with a consumer card attached. There’s a well documented workaround though, and with 5 extra lines in your XML, you can get them up and running.The rule of thumb with consumer Nvidia cards is that they all work with a little tweaking, more or less.
You can also drop a lot more money on a quadro and skip editing your xml, but we don’t recommend it.
AMD — some work, some just plain don’t
AMD has no such driver restriction for their consumer cards, which means (at least in theory) that they should “just work.” And a lot of them do. The trouble is, some of the AiB partners’ BIOS modifications don’t play well with KVM. A badly put together vBIOS can harm or even completely stop a passthrough gaming VM from working as intended. There are several bugs caused by this issue, that are collectively known as “The AMD Reset Bug.” There are 2 levels of severity:
- [*] Hang on Crash — The VM will work normally, but if it crashes during normal use, it will fail to reinitialize and will only become available again on system reboot. This is the less severe of the two levels, and may not affect the user at all if they aren’t overclocking or experiencing other system instability.
- [**] Hang on Reboot — The VM will work normally, but will fail to reinitialize after it is shut off, only becoming available when the host reboots. This level of the bug will make the card incredibly inconvenient to use for passthrough gaming.
There are workarounds that do work for some cards, but they aren’t as well documented or tested as the Nvidia Fixes, so we attempt to curate bug-free cards as best we can on this page.
Choosing the right motherboard is a twofold problem when it comes to VFIO. Not only do you need to carefully select for the right bios features and I/O, but you need to know how well the PCIe slots are isolated via IOMMU.
The problem is, no vendor lists the IOMMU layout on their boards, and the only information you can generally find is scattered in forum posts and may be years old. Furthermore, certain chipsets have quirks that, while known to community veterans, can stop newcomers in their tracks. Here, we provide personally (or in some cases community) vetted known working models for the range of products we recommend. If the part has issues that need working around, check the entry for asterisks, and reference them below.
UPDATE: as of AGESA 0.0.7.2 Mainstream Ryzen Motherboards Break VFIO entirely.
[*] – ACS needed in some cases: generally this workaround means that the board functions fine for regular use, but the cpu-specific lanes may not isolate properly. If you want a 2 dGPU build instead of using the iGPU or a chipset slot on these boards, the ACS Override Patch will generally be needed.
[**] – ACS needed in all cases: This board was chosen for price, not performance or compatibility. The IOMMU groups will not be functional for 1 GPU passthrough builds without the ACS patch.
[†] – CSM Toggle/Slot Swap: For these boards, the CSM module needs to be turned on/off in the UEFI to allow the host gpu to work properly, or GPUs need to be rearranged so that the system designates the correct GPU for boot.
[‡] – EFIFB off: the efifb option needs to be disabled for the host GPU to boot properly from the chipset slot.
If you have known working new AMD GPUs, please contact us with your make, model and the severity of the reset bug, if present.
Price totals are approximate and subject to change with the market. Also, please read our Affiliate Link Disclaimer.