Precision 7770 + NVidia RTX A1000 + dual HDMI 4K@60Hz

Question

Apologies for the long story followed by the short question.

Laptop: Precision 7770 i7-12850HX 32GB RAM NVidia RTX A1000 4GB

Dock: Plugable TBT4-UDZ

Monitors: LG 32UL950 (landscape), LG 27UL600 (portrait) both over HDMI

Problem: running in Discrete Mode or Hybrid Mode with Direct Output won't let me set both monitors to 4K@60Hz. If I try to force it, one monitor (portrait one) goes black even though content is still rendering/running as seen on taskbar thumbnails. 60Hz and 30Hz paired works until I fire up videos from any source (news/review site, streaming services, etc). 30Hz and 30Hz does similar.

Moving to one monitor on DisplayPort and the other on HDMI gets similar results.

Switching to dual DisplayPort connections works fine with 4K@60Hz and all video content, but my desktop is currently plugged into the DP connections.

Plain Hybrid Mode works fine all the way around both at 4K@60Hz and all video content works great. Only runs on Intel GPU though -- not a huge deal as a fallback.

The short question: Is the A1000 GPU limited in some way or is this a Dell implementation that isn't working over Thunderbolt 4? Am I hitting some kind of memory or performance limit of the A1000 with the monitors I have and the landscape/portrait combo?

Any assistance is appreciated.

GLap · Accepted Answer

One last reply to document the issue(s) for others to find:

Dell support, while responsive, has repeated replied with documents and references to the Dell WD22TB4 dock. I am led to believe through this and my testing (more on this later) that the Precision 7770 with the NVidia RTX A1000 -- and possibly other graphics cards -- is engineered to support only the connections available to that dock: 2x DisplayPort 1.4 and either of 1x HDMI or 1x Type-C.

My testing with the 7770 and the Plugable TBT4-UDZ connected via TB4 to two 4K monitors:

Terms:

Discrete == Discrete Graphics Mode where the A1000 handles all monitors

HGDO == Hybrid Graphics Mode with Direct Output - laptop display is on Intel graphics, external monitors on A1000

HG == Hybrid Graphics Mode - Both graphics cards are available, but all monitors generally run on the Intel graphics.

2x HDMI -- won't work above 4K@30Hz refresh in Discrete or HGDO. Didn't try lower resolutions. Any video content (streaming services, news/review sites, Youtube, etc) cause the screens to go black and only the laptop display works. Sound and desktop indicate content is rendering and running, but monitors are blank. HG works fine.
1x HDMI, 1x DP -- In Discrete or HGDO, DisplayPort monitor will do 4K@60Hz, but the HDMI drops to 4K@30Hz. HDCP content does not work. HG works fine.
2x DP -- everything is fine in all modes.

Notes:

If you're using all DisplayPort, you're golden.
If you get an active DisplayPort->HDMI converter (Plugable makes them), the entire issue is solved since the system thinks you're using 2x DP.
The dock is really fast and really nice, but you still need an external power brick attached to the laptop.
It'd be nice if Dell would document the limitations of the laptop instead of pointing users to the Dell-branded docks as an explanation of the laptop's limitations.

Asheville Hawker · Answer

While I can't answer your question I think I can tell you how to answer the question.
The Nvidia App has a page where it will tell you the maximum capability and output combinations of each port for the card it is running. That may answer your question about the cards ability.

Oh and how do you like the Plugable TBT4-UDZ?
I'm about to throw this dell WD22TB4 dock in the trash. It has so many different issues. I checked out the plugable (never heard of it before your post) and see it solved 90% of what I don't like about the Dell dock.

GLap · Answer

I have looked at the NVidia control panel and it claims everything is fine. HDCP capable and all running ok while one of the monitors sits at black screen. Even when I do get the desktop running ok, any access to video content drops both screens to black and only the laptop display works. The fact that the Intel graphics works everything fine through the dock and the DP connections work fine for both graphics systems makes me think there's some underlying implementation issue with the NVidia.

I did just notice that the PhysX config page in the NVidia control panel shows 3 DP and 1 HDMI on the graphics, but then the Intel UHD also shows only 2 DP, but works fine through the HDMI on the dock. Not sure if that's any indicator either.

The Plugable dock is super-fast and really nice if you're using the DP monitor connections for me.

I am not sure how well the dock lives up to the quad-connection capabilities advertised because I don't have four 4K monitors to test. However I'm not sure my Dell is up to the task since the Intel chip seems to drive things fine, but the NVidia card can't seem to do two at 4K@60Hz. However even using the Intel graphics to drive everything (i.e. plain Hybrid Mode) works more smoothly than my old USB3 DisplayLink dock.

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Precision 7770 + NVidia RTX A1000 + dual HDMI 4K@60Hz

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