Question Juddering when using Displayport, OK with USB-C

[jameshodge37]

Hi all, hoping someone can help point me in the right direction here. I'm experiencing some juddering which is reliably repeatable when using a specific combo of things, and I don't know where the problem lies.

I have a Razer Blade 15, 2070 RTX, it has displayport and thunderbolt.

Playing Kerbal Space Program, as my benchmark:

• Running directly on the laptop - smooth 144 fps.
• Running via a USB-C to DP cable to a 144Hz monitor (AOC G2460PF) - smooth as expected, 144fps.
• Using a mini-DP to DP cable, same monitor, it starts smooth, then starts juddering. It's not frame rate as FRAPS lists the same frame rate as other tests, but it is extremely noticeable juddering.

Some things of note.

1. I've used this monitor on another PC, with a DP to DP cable, and the frame rate was very smooth.
2. I've tried multiple miniDP to DP cables, including a brand new one specifically touted to handle 144Hz at 1080p.
3. If I turn the monitor to DP capability 1.1 and back to 1.2 it goes very smooth for a few seconds before juddering again.

So it is either, laptop's display port, or mini DP specifically.

I realise the easy solution is to use the USB-C cable, but I would really rather use the miniDP port as it helps the rest of my set up, and if there's a problem with the hardware, I'd like to know who to moan at.

Any help massively appreciated.

 

[Lutfij]

You might want to see if you have a BIOS update pending for the laptop. Apart from that you will need to uninstall and then reinstall your GPU drivers and see if that eliminates the issue. If the issue is on the DP alone, that might be due to a faulty port or driver.

 

[Prostar Computer]

Can you tell us the exact mini DP-to-DP cable you're using? Do you happen to know the DP version of the port on the laptop?