Steps to Reproduce:

1. Place down a few monitors
2. Place a GPU below the bottom-left-most monitor (so if the GPU were a computer, the peripheral side to connect to the monitor, if it could, would be "top")
3. GpuImpl.refreshSize()
4. GpuImpl.getSize() returns 0 0 0 0 16
5. Move the GPU to be on the same Y level as the bottom-left-most monitor, still adjacent
6. GpuImpl.refreshSize()
7. GpuImpl.getSize() returns a valid size (for a 5x5 monitor, it returns 80 80 5 5 16 by default)

Versions:

Tom's Peripherals: 1.3.0
CC:Tweaked: 1.112.0
NeoForge: 21.0.167
Minecraft: 1.21

Screenshot: