Pro 14 Plus PB14250, multiple external monitors plus laptop display

Third external as in internal screen plus two external monitors should work -- third external as in three externals plus the internal screen won't.  The GPU can only drive three simultaneous displays.  If you need three externals, you'll need USB Displaylink adapter for one of them.

What resolution are the monitors running?  The documentation for that TB hub state support for two 4K or one 8K monitor.

@ejn63​ The Alienware is at 3440x1440, the 2nd monitor should be around the same and the inter al is at 1920x1200

Try connecting the two monitors directly to the notebook (one to each Thunderbolt port).  If that works reliably, ask the manufacturer of the dock -- that 3440X1440 resolution isn't common to the Mac world and may be an issue with a Thunderbolt dock designed for Apple systems.

The reason I was trying to use the OWC dock was because I get periodic black screen and text morphing or blurryness on both monitors when used via the thunderbolt ports usb c to dp etc I thought the hub would fix that but it seems not to be the case

Hiya, both monitors work when directly plugged in but one or both will inevitably black screen for maybe 1-2 seconds and come back with distorted text on both Chrome and Edge and this is only fixed either by constant mouse movement or by unplugging the cable and replugging the cable and this holds for a few hours. The way I understood the hub should have been able to correct or filter out these issues but I am still now having the other issue of not having a 2nd external monitor just the laptops internal 1 and the Alienware 34 inch monitor

You're running up against the limitations of a model not designed for the workload you're assigning it -- it's a business class notebook that's really designed for running a max of one external monitor.  It's not designed to handle two high resolution gaming monitors.

Hub/dock or not, you need a system with a more capable GPU.

Even so I should not be getting black screen and text distortion on any screens and that was using direct dp usb c or hdmi usb c connections as it is now though it is a migraine every few hours and it's brand spanking new 😰

I miss the HP I had both monitors no issues but what to do work got a new contract and we had to return em all

Does the same thing happen with just one monitor connected?  Or with reduced resolution on one of the two external monitors?

Try lowering the Hz on both the AOC GAMING CU34G2X (144Hz max) and AW3423DWF (165Hz max) to 60Hz. Then retest.

Hi,

This sounds like a bandwidth/EDID issue rather than a faulty monitor. When running multiple ultrawide displays through a Thunderbolt 4 hub, Windows can struggle with resolution and refresh rate negotiation, often resulting in no signal, blurry output, or brief black screens.

I’d suggest trying a CRU download Windows 11 and manually checking or resetting the monitor EDID data. With Custom Resolution Utility, you can:

• Remove duplicate or conflicting resolutions

• Set a stable refresh rate (try 100Hz or 60Hz first on the AOC)

• Disable DSC or unsupported timings that may cause black screens

After applying changes, restart the graphics driver (CRU restart64) or reboot. Also make sure all displays are connected directly to the hub (not daisy-chained) and that your Intel/NVIDIA drivers are fully up to date.

This often resolves intermittent signal and blur issues with multi-ultrawide Thunderbolt setups.
cru download windows 11

Thanks all for the help provided so far but having looked at the admin locked Bio settings the Thunderbolt feature has been blocked by the admin department which might be the cause of it all and the reason the fix isn't working as the laptop will only see the OWC box as a normal usb hub

I'll update if and when I can get IT to activate the setting

It is recommended that troubleshoot from the following aspects:
1. Set the resolution of both external monitors to 1080P@60Hz to test whether the issue stems from excessively high resolution:

System---->Display---->Choose monitor-2 or 3---->Display resolution---->Choose resolution-"1080P"----->Advanced display---->Choose display-2 or 3---->Choose a refresh rate-"60Hz"

2. Update computer's graphics card driver.

I previously encountered display issues when using mokin hub, solved in this way, now both external monitors display normally.