MP 6,1 Mac Pro 2013 stuck at 50Hz

[Zeebedy]

Hey guys,

today i received a 2013 Mac Pro. Its all setup and am using a Thunderbolt 2 to DisPlay port cable.

When in 2K I can only get 50hz otherwise the display artifacts and the maximum it will allow at 2K is 75Hz??

Now, it could be the cable, not 100% sure, but it is 5M in length, could that be a factor??



thanks guys!

 

[capamac]

Yeah try a shorter cable mebbe.

 

[Zeebedy]

I’m sure the cable I bought doesn’t cut it either. It states 4k @ 60hz..

Ordered a new one 2m long and rated 4k @ 240hz, so surely will run 1440p @ 120hz..?

 

[capamac]

Dunno what the max refresh rates are on that particular Mac.

 

[TzunamiOSX]

I have an Eizo 4K connected to my mp6,1 with 3840x2880 @60 Hz. The cable is 3m long and work without problems

Cable Matters 8K Mini DisplayPort to DisplayPort 1.4 Cable, 3 m | 8K@60Hz, HDR, 32.4Gbps, Mini DP to DisplayPort 1.4, Black, Thunderbolt 1/2 Compatible

CONNECT MORE WITH Google DisplayPort Products Fully featured DisplayPort 1.4 cable The Mini DisplayPort to DisplayPort 1.4 cable is an essential companion for the latest computer or monitor with Mini DisplayPort or DisplayPort. DisplayPort 1.4 provides 1.5 times more bandwidth than DisplayPort...

www.amazon.de

I am relatively sure that the 6,1 does not support frequency’s over 60 Hz for digital displays.

 

[benholt]

TzunamiOSX has it right — the 6,1 tops out at 60Hz on digital. The FirePro D300/500/700 GPUs are DisplayPort 1.2, which caps at 4K@60Hz or 1440p@60Hz over a single link; anything above is out of spec for the machine, so your incoming 240Hz-rated cable won't unlock rates the GPU can't drive.
The 50-vs-75Hz weirdness with the 5m TB2 cable is a classic signal-integrity fail — Thunderbolt 2 passive copper degrades badly past ~2m and the monitor's EDID comes back partially garbled, so macOS picks a 'safe' PAL-adjacent rate. Your incoming 2m should sort it. If you ever need to go 3m+ from a 6,1, active TB2 cables exist but they're now rare and stupid expensive; usually cheaper to relocate the machine.