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In theory, it should work. In practice maybe not.
What laptop do you have?
CAC-1333 supports only DisplayPort 1.2 so it would be limited to 4K60.
https://insights.club-3d.com/thread/cac-1333-with-apple-studio-display-and-macbook-pro-early-2013/
Something like the CAC-1332 would be better because it includes USB 2.0 for the USB features of the display.
For higher resolutions (5K or 6K), the CAC-1336 supports HDMI 2.1 and DSC and also includes USB 2.0 but it might have issues. I have not tried it with an Apple 5K or 6K Thunderbolt display.
https://insights.club-3d.com/thread/cac-1336-operation/
The StarTech 148B-HDMI-DP-8K might have a slightly newer HDMI 2.1 to DisplayPort 1.4 chip (LT6711GX-U3 vs LT6711GX-U2 in the CAC-1336).
treytiderman
Thank you for your feedback!
I have the CAC-1333 already and the monitor but have not been able to get it to work. I tried a Dell Precision 3561 and a newer Mac Pro (2024) with no luck. The Mac Pro is actually what I wanted this to work with since the monitor is going to be too far from the Mac Pro to use a Thunderbolt cable. I also have tried forcing different EDIDs through some Crestron HDMI extenders with no luck. I believe it doesn’t work but maybe there is something I am missing. I haven’t been able to find anywhere that has confirmed there is a way to get a HDMI signal into an Apple Pro Display XDR
The CAC-1333 is supposed to produce a DisplayPort signal.
Have you tried a bidirectional DisplayPort to USB-C cable? It should be the same thing as the CAC-1333 – i.e. a DisplayPort signal with no USB data but without the HDMI conversion. If DisplayPort only works, then check the EDID for compatible display modes. You’ll need one that has a pixel clock < 600 MHz in order to fit in HDMI 2.0 bandwidth. Then, using the CAC-1333, see if that compatible display mode exists and has the same timing info (pixel clock, sync width, etc.). You can use SwitchResX to view timing info of the current display mode or any other display mode.
If you have an Intel Mac, then you can use my AllRez tool to get more info about the supported display modes.
The EDID of the XDR should have these modes:
[email protected] 89.818kHz 237.12MHz h(8 32 40 +) v(43 8 6 -) [email protected] 134.696kHz 528.01MHz h(8 32 40 +) v(59 8 582 -) [email protected] 134.686kHz 527.97MHz h(8 32 40 +) v(56 8 582 -) [email protected] 134.699kHz 528.02MHz h(8 32 40 +) v(8 8 518 -) [email protected] 134.684kHz 527.96MHz h(8 32 40 +) v(9 8 70 -) [email protected] 134.699kHz 528.02MHz h(8 32 40 +) v(7 8 70 -) [email protected] 134.699kHz 528.02MHz h(8 32 40 +) v(71 8 6 -) 16:9 [email protected] 179.531kHz 933.56MHz h(8 32 40 +) v(850 8 6 -) 16:9 [email protected] 179.567kHz 933.75MHz h(8 32 40 +) v(847 8 6 -) 16:9 [email protected] 179.550kHz 933.66MHz h(8 32 40 +) v(697 8 6 -) 16:9 [email protected] 179.519kHz 933.50MHz h(8 32 40 +) v(101 8 6 -) 16:9 [email protected] 179.579kHz 933.81MHz h(8 32 40 +) v(99 8 6 -) 16:9 [email protected] 210.940kHz 1285.89MHz h(8 32 40 +) v(1001 8 6 -) 16:9 [email protected] 210.960kHz 1286.01MHz h(8 32 40 +) v(997 8 6 -) 16:9 [email protected] 210.950kHz 1285.95MHz h(8 32 40 +) v(821 8 6 -) 16:9 [email protected] 210.928kHz 1285.82MHz h(8 32 40 +) v(121 8 6 -) 16:9 [email protected] 210.960kHz 1286.01MHz h(8 32 40 +) v(118 8 6 -) 16:9 preferred
The 1440p and 4K modes are within HDMI 2.0 limits.
HDMI 4K mode is 594 MHz and doesn’t match the XDR 4K modes. That means it would be a custom timing. I don’t know what custom timings work with the XDR.