9070 XT - 2x HDMI high refresh displays (144 and 120 Hz) not working

[King Mustard]

Seems most DP to HDMI adapters are not VRR compatible. -TBQH, I more than half-expected that, even though it's part of the HDMI2.1 specification. (see prior comments about 'fast and loose' specifications w/ HDMI, etc.)

I will give CalDigit/their ODM credit for giving the adapter some heatsinking, tho. Assuming, its thermally bonded inside, both ends are solid aluminum.
Right now, I'm using the adapter @ 4k 240hz 10-bit w/ HDR (DSC, I assume) through DP1, and 1080p 144hz 8-bit SDR on DP2.
-that should 'stress test' the adapter some


Even though my "CalDigit DP 2.0 -> HDMI 2.1" adapter is only handshaking HBR3 8.1Gbps/lane (according to Radeon Settings), I can set output to 4k240hz 10-bit RGB4:4:4 w/ HDR on my Sapphire Pulse RX 9070 XT, using the adapter. (I also have an old 144hz 1080P VG248QE connected on the other DP)

<screenshot snipped>
<photo snipped>
note: VRR is enable on the display, AMD Settings says it's unavailable, on the PC-side.
Apparently, DSC is working


Your adapter appears to be the (*resolvable) problem point. Plausibly, related to DSC version differences.
DP 1.4 is associated to DSC 1.2.
DP 1.4a, 2.0, 2.1 and 2.1a are associated to DSC 1.2a.


*Clearly, your current adapter worked w/ the 3080, and doesn't w/ the 9070XT. -and clearly, AMD has a part in this fault.

However, another newer spec active adapter is capable of meeting your needs/expectations.
Upgrading the adapter is the easiest and most affordable solution.

Edit: There's a chance you might be able to update the firmware on your current adapter, to address this compatibility issue.
Might not even need to upgrade, just update

Cable Matters Firmware Update Tool [4k@120hz on macOS] - Cable Matters Knowledge Base

I updated the firmware a few months ago (possibly December or January) but apparently that article was updated on March 17, 2025, so I downloaded the update tool again, which said it had updated the device to 7.02.126. The tool did not state was the previous version was.

It appears I can now run the display at 4K120 10 bpc, as long as the Pixel Format is:

• YCbCr 4.2.0
• YCbCr 4.2.2

It will not work at 4K120 8 bpc or 10 bpc:

• RGB 4:4:4 Studio (Limited RGB)
• RGB 4:4:4 PC Standard (Full RGB)

 

[LabRat 891]

I updated the firmware a few months ago (possibly December or January) but apparently that article was updated on March 17, 2025, so I downloaded the update tool again, which said it had updated the device to 7.02.126. The tool did not state was the previous version was.

It appears I can now run the display at 4K120 10 bpc, as long as the Pixel Format is:

• YCbCr 4.2.0
• YCbCr 4.2.2

It will not work at 4K120 8 bpc or 10 bpc:

• RGB 4:4:4 Studio (Limited RGB)
• RGB 4:4:4 PC Standard (Full RGB)

Well, at least it's an improvement. Looks like a upgraded adapter might be required.

 

[King Mustard]

Well, at least it's an improvement. Looks like a upgraded adapter might be required.

As with HDMI cables, trying to find a quality HDMI to DisplayPort active adapter that follows the specifications is a minefield.

 

[R-T-B]

I bought this model of RX 9070 XT specifically because it has 2x HDMI ports, so I no longer needed an active adapter.

Yes but are they both hdmi 2.1 ports? I kind of doubt it as few cards from any vendor feature that, and that would absolutely explain this.

As with HDMI cables, trying to find a quality HDMI to DisplayPort active adapter that follows the specifications is a minefield.

As long as you don't need VRR its rather easy. Add VRR and its a minefield yes.

 

[King Mustard]

Yes but are they both hdmi 2.1 ports? I kind of doubt it as few cards from any vendor feature that, and that would absolutely explain this.


As long as you don't need VRR its rather easy. Add VRR and its a minefield yes.

I did not check as I did not think a mid-high-end GPU in 2025 would not support HDMI 2.1 (which came out in 2017) on both ports.

 

[OldMan]

Yes but are they both hdmi 2.1 ports? I kind of doubt it as few cards from any vendor feature that, and that would absolutely explain this.


As long as you don't need VRR its rather easy. Add VRR and its a minefield yes.

I saw one review of a DisplayPort adapter on Amazon say that VRR worked when they bought it a few months ago. So, they bought two more of the same brand and neither of those supported VRR. I think the supplier used different internals for a refresh while keeping the brand/shell of the product. I didn't buy that product because the reviews were so mixed, either great or awful.

 

[LabRat 891]

As with HDMI cables, trying to find a quality HDMI to DisplayPort active adapter that follows the specifications is a minefield.

As long as you don't need VRR its rather easy. Add VRR and its a minefield yes.

Indeed. If VRR(FreeSync) isn't a necessity, I've confirmed the CalDigit DP2.0-HDMI2.1 adapter will do:

4K120 8 bpc or 10 bpc:

• RGB 4:4:4 Studio (Limited RGB)
• RGB 4:4:4 PC Standard (Full RGB)

-and higher.

I did not check as I did not think a mid-high-end GPU in 2025 would not support HDMI 2.1 (which came out in 2017) on both ports.

Yes but are they both hdmi 2.1 ports? I kind of doubt it as few cards from any vendor feature that, and that would absolutely explain this.

Both ports support HDMI 2.1 48Gbps, but they seem* to share bandwidth.
I can plug my 4K240 LG 32" OLED into either HDMI port on my RX 9070 XT, and I get full 4K240hz 10-bit HDR VRR over HDMI 2.1.


*Oddly enough, (at the moment of writing) I have my old VG248QE plugged in via HDMI1.4 @ FHD60hz 8-bit SDR alongside my LG 32" 4K240hz 10-bit HDR VRR OLED via HDMI2.1
without seemingly any compromise to the LG's connection. -using either port, for either display. (I just tested it as I edited this post)
So, I'm not quite sure how exactly Sapphire has implemented the 2nd HDMI2.1 port...

 

[King Mustard]

Indeed. If VRR(FreeSync) isn't a necessity, I've confirmed the CalDigit DP2.0-HDMI2.1 adapter will do:

-and higher.



Both ports support HDMI 2.1 48Gbps, but they seem* to share bandwidth.
I can plug my 4K240 LG 32" OLED into either HDMI port on my RX 9070 XT, and I get full 4K240hz 10-bit HDR VRR over HDMI 2.1.


*Oddly enough, (at the moment of writing) I have my old VG248QE plugged in via HDMI1.4 @ FHD60hz 8-bit SDR alongside my LG 32" 4K240hz 10-bit HDR VRR OLED via HDMI2.1
without seemingly any compromise to the LG's connection.
So, I'm not quite sure just how Sapphire implemented the 2nd HDMI2.1 port...

Unfortunately, the CalDigit DP20-HDMI21 appears to be US-only.

I would prefer to find a solution that can ship from within the UK.

 

[R-T-B]

Unfortunately, the CalDigit DP20-HDMI21 appears to be US-only.

I would prefer to find a solution that can ship from within the UK.

If you don't need VRR I have had luck with the Club3D CAC-1085.

I'm not a fan of the CalDigit solution as though it works fine it kind of falsely represents itself as being displayport 2.0 while its really only bandwidth-ready for 1.4 speeds. I wrote about this deception in an ancient post, somewhere. Thus its no better than the Club3D parts, which at least historically, were more globally available.

And don't get me wrong, it is indeed quite backwards that this scenario exists at all. But here we are.

 

[OldMan]

If you don't need VRR I have had luck with the Club3D CAC-1085.

I'm not a fan of the CalDigit solution as though it works fine it kind of falsely represents itself as being displayport 2.0 while its really only bandwidth-ready for 1.4 speeds. I wrote about this deception in an ancient post, somewhere. Thus its no better than the Club3D parts, which at least historically, were more globally available.

And don't get me wrong, it is indeed quite backwards that this scenario exists at all. But here we are.

I could get my Sony TV to display 4K@60Hz 4:4:4 and my LG C2 OLED to work at 4K@120Hz 4:2:0 but it was flakey as all get out. I was expierencing black screens at every start up and wake from sleep. The only way I could get my computer to start (with a screen active) was to unplug the HDMI ports, power down the PC and leave only the Acer 1440p monitor connected thru display port. Then I would connect the Sony and LG but the LG usually defaulted to 1080p or 1440p. Then I would change the C2 to 4K@120Hz 4:2:0. The only reason I thought to change the color depth to 4:2:0 was because that's what it defaulted to a few times and I remembered that required a lower bandwidth.

I tried both 25.3.1 and 25.3.2 drivers with no change to the black screens at startup. The only solution that worked was using only one device thru the HDMI ports. That with the Sony connected with a display port adapter I haven't seen another black screen at start up.

 

[LabRat 891]

Unfortunately, the CalDigit DP20-HDMI21 appears to be US-only.

I would prefer to find a solution that can ship from within the UK.

They do have a UK site, but they are OoS

Active DisplayPort 2.0 to HDMI 2.1 Adapter

shop.caldigit.com

Take the source confirming it works as-expected FWIW, but this is the only other UK-avail adapter/cable that even claims DP2.0->HDMI2.1


goobay 64848 - DisplayPort 2.0 to HDMI 2.1 8k @ 60Hz Cable/DP to HDMI Connection Cable / 4K @ 144Hz High Speed Cable / 5M @ Amazon.co.uk

https://www.fruugo.co.uk/64848-displayport-20-to-hdmi-21-8k-60hz-cabledp-to-hdmi-connection-cable-4k-144/p-339692529-745111108

If you don't need VRR I have had luck with the Club3D CAC-1085.

I'm not a fan of the CalDigit solution as though it works fine it kind of falsely represents itself as being displayport 2.0 while its really only bandwidth-ready for 1.4 speeds. I wrote about this deception in an ancient post, somewhere. Thus its no better than the Club3D parts, which at least historically, were more globally available.

And don't get me wrong, it is indeed quite backwards that this scenario exists at all. But here we are.

Club 3D | CAC-1085 The Ultimate Connection for DP to HDMI 4K120H

The Ultimate Connection for DP to HDMI 4K120HzDisplayPort™ 1.4 to HDMI™ 4K120Hz HDR Active Adapter M/FThe Club 3D CAC-1085 is the perfect solution to connect to any HDMI™ 4K120Hz ready displays*. If you have a DisplayPort™ 1.4 ready PC or any other device that lacks the new HDMI™ 4K120Hz...

www.club-3d.com

Unfortunately for King Mustard, it's not especially available, especially not in the UK.

OtOH, the CAC-1087 cable and CAC-1088 dongle would be the more-modern functional replacements for the CAC-1085.

Active Cable:

Amazon.co.uk

Active Dongle:

Amazon.co.uk

https://www.scan.co.uk/products/club3d-cac-1088-displayport-14-male-to-hdmi-21-female-active-adapter-4k120hz-8k60hz-hdr10plus-hdcp-2

 

[R-T-B]

Take the source confirming it works as-expected FWIW, but this is the only other UK-avail adapter/cable that even claims DP2.0->HDMI2.1

As mentioned earlier, it's misleading and actually using DSC at DP1.4 speeds. Worse yet, it uses a higher degree of DSC than the club3d adapter. I actually took apart it's edid to confirm all this.

Beyond those two parts I haven't tried anything else, but they do exist anyways. And the DSC at this level on either adapter really isn't noticable.

OtOH, the CAC-1087 cable and CAC-1088 dongle would be the more-modern functional replacements for the CAC-1085.

This is possible, the Club3d part I've used for years but never looked at replacements in their catalog. It is a hot litlle unit too, to it's detriment, and while it doesn't require active cooling or anything, it does need an external power source. So probably old tech.

 

[Phil_Libra]

Hey, I found a temporal solution for you (and me):
There's a HDMI 2.1 port on your MB and your can connect one TV to it.
I tested on my X670E Carbon and my monitor (Dell U2725QE) works perfect, 4K 120Hz 12bit RGB 4:4:4 with VRR enable.
Later I will buy a GIGABYTE 9070XT and test if there's any dual HDMI problem.

 

[LabRat 891]

Hey, I found a temporal solution for you (and me):
There's a HDMI 2.1 port on your MB and your can connect one TV to it.
I tested on my X670E Carbon and my monitor (Dell U2725QE) works perfect, 4K 120Hz 12bit RGB 4:4:4 with VRR enable.
Later I will buy a GIGABYTE 9070XT and test if there's any dual HDMI problem.

In my limited experience*, this is only truly viable on Windows 11 (or Linux? ).
On windows 10, leaving IGPs integrated w/ a dGPU has been a PITA.

Otherwise, a great workaround (if applicable).

*My own A320M-K+4600G+6500XT
and
my friend's Gigabyte Aorus B650 Elite+7900X and 7800X3D+7900XTX.

 

[eidairaman1]

Hey, I found a temporal solution for you (and me):
There's a HDMI 2.1 port on your MB and your can connect one TV to it.
I tested on my X670E Carbon and my monitor (Dell U2725QE) works perfect, 4K 120Hz 12bit RGB 4:4:4 with VRR enable.
Later I will buy a GIGABYTE 9070XT and test if there's any dual HDMI problem.

You have 2x 120 mhz monitors the op has 2 different monitors

 

[OldMan]

Hey, I found a temporal solution for you (and me):
There's a HDMI 2.1 port on your MB and your can connect one TV to it.
I tested on my X670E Carbon and my monitor (Dell U2725QE) works perfect, 4K 120Hz 12bit RGB 4:4:4 with VRR enable.
Later I will buy a GIGABYTE 9070XT and test if there's any dual HDMI problem.

I saw that Gigabyte has at least 3 different RX 9070XT versions, all with duel HDMI ports. The only one I could find in stock is the Gigabyte Gaming Radeon RX 9070 XT bundled with a Gigabyte B850 Gaming motherboard for $909 on Newegg. I am definitely interested if those cards have the same bandwidth limitations or if the problem is only with the Sapphire card.

 

[Phil_Libra]

In my limited experience*, this is only truly viable on Windows 11 (or Linux? ).
On windows 10, leaving IGPs integrated w/ a dGPU has been a PITA.

Otherwise, a great workaround (if applicable).

*My own A320M-K+4600G+6500XT
and
my friend's Gigabyte Aorus B650 Elite+7900X and 7800X3D+7900XTX.

Yes, I tested on Windows 11, IGP works perfect with 6900XT(DP connect). But I haven't test dual HDMI connection because I have only one HDMI 2.1 cable now.

 

[LittleBro]

Don't get Gigabyte RX 9000 cards. Get anything else.

 

[LabRat 891]

Don't get Gigabyte RX 9000 cards. Get anything else.

Most-recently:

Gigabyte graphic card - TIM GEL application failure?

After inspecting a Gigabyte RTX 5070 Ti Gaming OC card with unusually strong smell, about which I reported here: https://www.techpowerup.com/forums/threads/smelly-brand-new-graphic-cards-remanufactured.334706/ I discovered, that my particular sample (SN 250641092344) seems to have pretty large...

www.techpowerup.com

My own recent-ish "Gigabyte Experience" on a BNIB Sealed from Newegg, Launch RX 7900 GRE:

 

[Phil_Libra]

Don't get Gigabyte RX 9000 cards. Get anything else.

Gigabyte is the only brand offers 4yr warranty in my country. And also the only brand has dual HDMI 9070XT except Sapphire.

 

[LittleBro]

Most-recently:

Gigabyte graphic card - TIM GEL application failure?

After inspecting a Gigabyte RTX 5070 Ti Gaming OC card with unusually strong smell, about which I reported here: https://www.techpowerup.com/forums/threads/smelly-brand-new-graphic-cards-remanufactured.334706/ I discovered, that my particular sample (SN 250641092344) seems to have pretty large...

www.techpowerup.com

My own recent-ish "Gigabyte Experience" on a BNIB Sealed from Newegg, Launch RX 7900 GRE:

Mostly for that fan clicking sound. It's extremely annoying.

 

[LabRat 891]

Mostly for that fan clicking sound. It's extremely annoying.

Funny.
There's a Gigabyte GTX 1080Ti in my friend's collection that had the same issue.
Dunno if same cause but, I 'fixed it' by taking a lighter to the fan fascia+LEDdiffuser, bending it away from the fan.
I doubt it was always that way, since it was a secondhand eBay purchase, but the plastic looked like it was already 'overshrunk' or warped when it came out of the mold, years-ago.

@ OP
If you end up having to run dual cards or use iGPU+dGPU, you might find some additional boons, for the trouble

-2nd adapter connected to primary display, can take all the load for AFMF or LosslessScaling.

 

[Phil_Libra]

Hey guys,I got my AORUS RX 9070 XT ELITE today and tested dual HDMI solution.
The 1st monitor comes with 4K 120Hz 12bit RGB444 but the 2nd monitor with only 4K 120Hz 8bit YCbCr 420.
Even when I set the 1st one to 4K 120Hz 10bit RGB444, no 10bit or RGB 444 for the 2nd.
I think there's no AMD card can have dual 4K 120Hz 10bit RGB444 HDMI signal now.
But someone in Chinese forum Chiphell found a DP 1.4 to HDMI 2.1 adapter have VRR support:https://www.chiphell.com/forum.php?mod=viewthread&tid=2695326