Saturday, September 21, 2024

8K display on laptop

 I've upgraded the display I use at my desk to a 65" Samsung QN800C, which is an 8K display.  I bought it open-box at a Best Buy Outlet for $1349.


The ThinkPad T14s Gen3 that I have drives it natively at 60 fps, even though the Lenovo documentation does not mention that this is a supported configuration.  There were a few things I had to tweak to make the setup work.  I thought I'd share because I spent way too much time trying to figure this stuff out before the purchase.

  • I needed a high bandwidth 8K capable HDMI cable.
  • The monitor must be set to Game Mode On, Intelligent Mode Off
  • Quite a bit of futzing with the picture settings to get colors which are even moderately acceptable.  I build cameras but I mostly look at SolidWorks, spreadsheets, and circuit designs, so I can live with terrible color.  If you do photography for a living, do not buy this setup, it will not work for you.
    • Brightness 50
    • Contrast 50
    • Sharpness 10
    • Color 11
    • Tint G0/R0
  • The machine was occasionally taking "coffee breaks" of up to 30 seconds when switching focus between different application windows.  This got particularly bad when SolidWorks was running, especially with the SolidWorks window expanded to full screen.  The fix is to change the "UMA frame buffer size" in the BIOS from "Auto" to "4GB".  I have no idea if 2GB would work, I didn't try it.  This also eliminates the frequent warnings from SolidWorks about insufficient system resources.
The display has 187 micron pixels, vs the 157 micron pixels on my laptop screen.  I have it positioned about twice as far away, however, 35 inches from my face.  It's actually mounted to the wall and my desk sits several inches from that wall.  I find a 150% scale factor on the laptop display and a 175% scale factor on the 8K display work well.

The surface of the display is around 103 degrees F, compared to my laptop screen which is 79 F.  I'm not sure why this is, but it's annoying.  The screen takes up a large enough solid angle from my face that I actually feel a little heat from it, which I dislike.  It's a little like the effect of being near a campfire.  I can eliminate the feeling by blowing a 4" desk fan at the screen, which takes the surface down to the 80s.  Even though that fan is "quiet", this is too noisy for me.  I've purchased a couple of very quiet Sanyo Denki fans, which I'm going to mount behind the screen, along with a yet-to-be-designed 3D printed plenum that will reach under the screen and direct a thin sheet of air up the face.

Overall, I'd say it's useful enough to be worth it.  I park a web browser on the left, and a Word file with notes on the right, and mostly use the center of the screen.  I find I'm still using my laptop display as well.  Maybe I'm just a slob and I like to spread out.