Is there any way to get displayport passthrough with an unsupported motherboard?

[Shouko]

As the post title says, my motherboard doesn't have native DP passthrough but I'm looking for any possible way to use my GPU with my thunderbolt hub.

I have a CalDigit TS4 because I frequently swap between my laptop and PC, currently I have two cables running to each monitor and I manually swap between the inputs when I want to use either system. Anyone here have any ideas for getting this automated either via the thunderbolt hub or something while keeping use of the GPU?

I've looked into using an Asus ThunderBoltEX 4 card, but the maximus XIII Hero doesn't have a TB_HEADER port on the board (or at least I couldn't find it in the manual). I haven't looked into other thunderbolt 4 cards yet, but I was going to go over to my local computer shop later today to see if they have anything that might work. 

I appreciate any ideas anyone here might have, this is my first time using thunderbolt accessories so I'm pretty fresh to this side of things.

Thanks in advance! 

[adm0n]

Adding Thunderbolt to a not support motherboard is sadly impossible, as it needs the support for some of the thunderbolt functionality to work.

 

That being said, you could get USB-C with DP alt mode to work -> https://dancharblog.wordpress.com/2020/07/20/add-usb-c-with-dp-alt-mode-to-your-desktop-pc/

I don't think that will solve your problem though, as people have reported, that you can't have 2 monitors on your Thunderbolt hub, while it works in USB-c mode.

 

Another option for you would be to either use a HDMI-switch. (So two HDMI inputs and one HDMI output. You press a button for it to switch the input from the one input to the other one). There are passive switches and active ones, the active ones can detect which HDMI input is currently sending a signal and switch automatically. Not sure how well this works though. (Active in this sense means, that they need to be powered).

 

 

[TimedPing]

7 minutes ago, Shouko said:

As the post title says, my motherboard doesn't have native DP passthrough but I'm looking for any possible way to use my GPU with my thunderbolt hub.

I have a CalDigit TS4 because I frequently swap between my laptop and PC, currently I have two cables running to each monitor and I manually swap between the inputs when I want to use either system. Anyone here have any ideas for getting this automated either via the thunderbolt hub or something while keeping use of the GPU?

I've looked into using an Asus ThunderBoltEX 4 card, but the maximus XIII Hero doesn't have a TB_HEADER port on the board (or at least I couldn't find it in the manual). I haven't looked into other thunderbolt 4 cards yet, but I was going to go over to my local computer shop later today to see if they have anything that might work. 

I appreciate any ideas anyone here might have, this is my first time using thunderbolt accessories so I'm pretty fresh to this side of things.

Thanks in advance! 

I have trouble understanding your post (sorry I'm not natively speak English). My understanding is your PC motherboard have built-in thunderbolt capability, but doesn't have video input (passtrough) from your motherboard to Video card, and you're using thunderbolt dock to plug-in your display output. if that's so, there's a workaround if you're using windows 10 (and 11) and also having non-F intel CPU (with iGPU built-in)

So here's the step you can replicate:

• Go to windows settings
• Go to display settings
• Scroll down until you see "graphic settings" option
• In graphic settings, you can manage individual apps that can use either your iGPU or dGPU
• You manually (sorry, I know it's tedious) select each program/games to bypassed to your iGPU from dGPU
• Restart your system, then run some games/app that you configured with dGPU option earlier, verify that your dGPU is handling the works via task manager

The limitation of this process is your have some extra latency (mostly not noticeable), 1st, from extra routing back and forth from your dGPU to iGPU, and 2nd, converting it into Thunderbolt DP protocol and decoding it into your display via the TB docks.

This method is widely used in the past, even before thunderbolt is a big thing, mainly by AMD and NVIDIA (Nvidia optimus) back in the old days when laptop mfg didn't equipped their laptop with dedicated display MUX chip, and at the same time windows didnt natively support it yet. Or in more "bizarre" one is when you tried to hack GPU that didn't have dedicated display output like mining cards/NVIDIA Tesla/AMD Instinct GPU, this method works exactly the same.

 

[TimedPing]

1 minute ago, TimedPing said:

I have trouble understanding your post (sorry I'm not natively speak English). My understanding is your PC motherboard have built-in thunderbolt capability, but doesn't have video input (passtrough) from your motherboard to Video card, and you're using thunderbolt dock to plug-in your display output. if that's so, there's a workaround if you're using windows 10 (and 11) and also having non-F intel CPU (with iGPU built-in)

So here's the step you can replicate:

• Go to windows settings
• Go to display settings
• Scroll down until you see "graphic settings" option
• In graphic settings, you can manage individual apps that can use either your iGPU or dGPU
• You manually (sorry, I know it's tedious) select each program/games to bypassed to your iGPU from dGPU
• Restart your system, then run some games/app that you configured with dGPU option earlier, verify that your dGPU is handling the works via task manager

The limitation of this process is your have some extra latency (mostly not noticeable), 1st, from extra routing back and forth from your dGPU to iGPU, and 2nd, converting it into Thunderbolt DP protocol and decoding it into your display via the TB docks.

This method is widely used in the past, even before thunderbolt is a big thing, mainly by AMD and NVIDIA (Nvidia optimus) back in the old days when laptop mfg didn't equipped their laptop with dedicated display MUX chip, and at the same time windows didnt natively support it yet. Or in more "bizarre" one is when you tried to hack GPU that didn't have dedicated display output like mining cards/NVIDIA Tesla/AMD Instinct GPU, this method works exactly the same.

 

Here my screenshot for more clarity (Sorry my PC doesn't have iGPU so it's only showing 1 GPU)

[Shouko]

 

2 minutes ago, adm0n said:

Adding Thunderbolt to a not support motherboard is sadly impossible, as it needs the support for some of the thunderbolt functionality to work.

 

That being said, you could get USB-C with DP alt mode to work -> https://dancharblog.wordpress.com/2020/07/20/add-usb-c-with-dp-alt-mode-to-your-desktop-pc/

I don't think that will solve your problem though, as people have reported, that you can't have 2 monitors on your Thunderbolt hub, while it works in USB-c mode.

 

Another option for you would be to either use a HDMI-switch. (So two HDMI inputs and one HDMI output. You press a button for it to switch the input from the one input to the other one). There are passive switches and active ones, the active ones can detect which HDMI input is currently sending a signal and switch automatically. Not sure how well this works though. (Active in this sense means, that they need to be powered).

 

 

my motherboard has Thunderbolt 4, just only with integrated GPU support. Or at least, I'm unaware of any discrete GPU passthrough support on the board. Would the same still apply? I know with my laptop, both monitors do work over my TS4 and on the PC they both do show up, but with the iGPU instead of the dGPU (or at least thats what happens when I use just the TS4 for all inputs/outputs. 

As for a switch, that could work! I might see if its possible to have some form of automation/logic with an active switcher so it switches with the hub.

[Shouko]

7 minutes ago, TimedPing said:

I have trouble understanding your post (sorry I'm not natively speak English). My understanding is your PC motherboard have built-in thunderbolt capability, but doesn't have video input (passtrough) from your motherboard to Video card, and you're using thunderbolt dock to plug-in your display output. if that's so, there's a workaround if you're using windows 10 (and 11) and also having non-F intel CPU (with iGPU built-in)

This might work! I didn't realize Windows 10/11 had this functionality built into it, I'll try this real quick! and yes your understanding is correct. My PC has TB4 but not display passthrough (thanks Asus). Would that solution be persistent or would it reset with every windows update (if you know)? My windows install sometimes likes to reset settings back to default whenever it updates

[adm0n]

2 minutes ago, Shouko said:

my motherboard has Thunderbolt 4, just only with integrated GPU support. Or at least, I'm unaware of any discrete GPU passthrough support on the board. Would the same still apply? I know with my laptop, both monitors do work over my TS4 and on the PC they both do show up, but with the iGPU instead of the dGPU (or at least thats what happens when I use just the TS4 for all inputs/outputs. 

I just saw that too. So what you can always do, is "stream" the video output from your dGPU to your iGPU, even if GPU passthrough itself isn't supported on your device.

You'd basically tell your GPU that a monitor is connected (via a dummy plug for example) and if you lucky all you need to do is duplicate the screens in either the nvidia or windows settings. You could try out if this works for you, by just connecting one of your monitors via the dGPU and one via the iGPU and check if you can duplicate them.

 

You might run into some weird behavior though. Same as with the method @TimedPing suggested. There are always programs that refuse to run on the correct GPU or you need to fiddle around with them a bit until it works (at least that is what I could gather from reading through some posts from people who tried this)

[TimedPing]

5 minutes ago, Shouko said:

This might work! I didn't realize Windows 10/11 had this functionality built into it, I'll try this real quick! and yes your understanding is correct. My PC has TB4 but not display passthrough (thanks Asus). Would that solution be persistent or would it reset with every windows update (if you know)? My windows install sometimes likes to reset settings back to default whenever it updates

It's is working lol, I do it on my older Gigabyte Z170x G1 Gaming + i7 7700K with GTX 970 back in 2020, connected to LG ultrafine 5K monitor. But still, fingers crossed

[Shouko]

17 minutes ago, adm0n said:

I just saw that too. So what you can always do, is "stream" the video output from your dGPU to your iGPU, even if GPU passthrough itself isn't supported on your device.

You'd basically tell your GPU that a monitor is connected (via a dummy plug for example) and if you lucky all you need to do is duplicate the screens in either the nvidia or windows settings. You could try out if this works for you, by just connecting one of your monitors via the dGPU and one via the iGPU and check if you can duplicate them.

 

You might run into some weird behavior though. Same as with the method @TimedPing suggested. There are always programs that refuse to run on the correct GPU or you need to fiddle around with them a bit until it works (at least that is what I could gather from reading through some posts from people who tried this)

14 minutes ago, TimedPing said:

It's is working lol, I do it on my older Gigabyte Z170x G1 Gaming + i7 7700K with GTX 970 back in 2020, connected to LG ultrafine 5K monitor. But still, fingers crossed

Turns out that the Intel UHD 630 iGPU in my 10900k might be locked to 4K 30 Hz max, which makes both options not work unfortunately  ah well, it was a good try though!! Thank you both for the help! Silver lining though; this can be an excuse to get wife approval for an upgrade in the near future haha

[adm0n]

4 minutes ago, Shouko said:

Turns out that the Intel UHD 630 iGPU in my 10900k might be locked to 4K 30 Hz max

It isn't. Maximum DP resolution is 4k/60Hz. And thunderbolt 4 should support DP 2.0, which can do even more. On HDMI it is 4k/30hz.

 

Don't give up!

[TimedPing]

5 minutes ago, Shouko said:

Turns out that the Intel UHD 630 iGPU in my 10900k might be locked to 4K 30 Hz max, which makes both options not work unfortunately  ah well, it was a good try though!! Thank you both for the help! Silver lining though; this can be an excuse to get wife approval for an upgrade in the near future haha

Yeah, despite using high-end motherboard and your iGPU support 4K60 in DP lane, probably is Asus or Caldigit fault, as you know Thunderbolt is very troublesome thx to its closed-sourced nature. You can either buying other motherboard or just upgrade to 12/13th gen platform. It's my pleasure to help you. There's another solution but it's pretty expensive. Despite your motherboard lacking TB_Header, you can trick it to work, because that header only function is for security protocol. There's Wendell from Level1Tech video that teach you how to bypass that.

[TimedPing]

5 minutes ago, adm0n said:

It isn't. Maximum DP resolution is 4k/60Hz. And thunderbolt 4 should support DP 2.0, which can do even more. On HDMI it is 4k/30hz.

 

Don't give up!

Just give up! remember we handling both Intel vague and closed-sourced thunderbolt protocol and Asus motherboard here

[Shouko]

Just now, adm0n said:

It isn't. Maximum DP resolution is 4k/60Hz. And thunderbolt 4 should support DP 2.0, which can do even more. On HDMI it is 4k/30hz.

 

Don't give up!

Maybe its a windows/setup issue? 

I'm running PC -> CalDigit TS4 via a TB4 cable, and then DP 2.0 -> Monitor 1 (4K) alongside another daisy chained 1440p TB4 -> DP1.4 adapter, so maybe its a bandwidth limitation? Let me try again! 

 

1 minute ago, TimedPing said:

Despite your motherboard lacking TB_Header, you can trick it to work, because that header only function is for security protocol. There's Wendell from Level1Tech video that teach you how to bypass that.

Ohhhh I might look into that, that would be the ideal solution! Lemme go watch that video, since that would let me use the ThunderBoltEX 4 card. I also don't blame CalDigit for this though, using my MacBook Pro with the one thunderbolt 4 cable it runs both monitors at full resolution and refresh rate (144Hz on 4K monitor, 165Hz on 1440p monitor). Asus? 100% at fault though, they had the DP passthrough tech in this generation iirc but didn't put it on their Hero board for whatever reason. Still don't on 12/13th gen

[TimedPing]

1 minute ago, Shouko said:

I'm running PC -> CalDigit TS4 via a TB4 cable, and then DP 2.0 -> Monitor 1 (4K) alongside another daisy chained 1440p TB4 -> DP1.4 adapter, so maybe its a bandwidth limitation? Let me try again! 

Nah, modern thunderbolt controller is smart enough to handle the bandwidth of all that hardware, except asus using 1st gen thunderbolt 3 controller on their high end here

[Shouko]

2 minutes ago, TimedPing said:

Nah, modern thunderbolt controller is smart enough to handle the bandwidth of all that hardware, except asus using 1st gen thunderbolt 3 controller on their high end here

Unfortunately, Asus likes to cheap out on plenty of things. When I do upgrade I don't think I'll be going Asus though. They've been a nightmare support-wise, but I've been so disconnected from the PC market since 10th gen that I'm not 100% sure which manufacturer is "good" now

[TimedPing]

54 minutes ago, Shouko said:

Unfortunately, Asus likes to cheap out on plenty of things. When I do upgrade I don't think I'll be going Asus though. They've been a nightmare support-wise, but I've been so disconnected from the PC market since 10th gen that I'm not 100% sure which manufacturer is "good" now

Same here, didn't really follow consumer PC hardware since Ryzen 3000 launched, I mainly focused on embedded and server hardware (because that's my job). On that note, asus acquire their "cheapskate" mentality to their Asustor spun-off, and dammit, their system is best bang for the buck on the market right now. Instead using more expensive Atom C/Xeon D CPU for their "bottom-midrange" system, they use clever tricks including using cheap PCIe switch chip, cutting corners where it's not needed, and that's good product design mentality for embedded hardware right there.

[adm0n]

1 hour ago, Shouko said:

Maybe its a windows/setup issue? 

I'm running PC -> CalDigit TS4 via a TB4 cable, and then DP 2.0 -> Monitor 1 (4K) alongside another daisy chained 1440p TB4 -> DP1.4 adapter, so maybe its a bandwidth limitation? Let me try again! 

 

Ohhhh I might look into that, that would be the ideal solution! Lemme go watch that video, since that would let me use the ThunderBoltEX 4 card. I also don't blame CalDigit for this though, using my MacBook Pro with the one thunderbolt 4 cable it runs both monitors at full resolution and refresh rate (144Hz on 4K monitor, 165Hz on 1440p monitor). Asus? 100% at fault though, they had the DP passthrough tech in this generation iirc but didn't put it on their Hero board for whatever reason. Still don't on 12/13th gen

Ah, didn't think of that. I checked, and I think the iGPU only supports dp 1.2, so just one monitor 4k 60hz at 10bit. So I guess you wouldn't have enough bandwidth left over for a second monitor :c sad