I am trying to understand how the PCIe 3.0 4x lanes of thunderbolt 3/4 impacts my ability to drive multiple high resolution displays through a eGPU. I want to use a eGPU to drive (3) external displays: (1) 5K display and (2) 4K displays. Let's take an extreme case to illustrate this question, I am looking at the Nvidia Quadro T1000 which supports driving (4) 5K displays at 60hz. Will this max out the PCIe 3 4x link of thunderbolt or is a lot less data transmitted between the CPU and GPU than between the GPU and monitors?
To do: Create my signature with system and expected eGPU configuration information to give context to my posts. I have no builds.
.
A lot less data transmitted between CPU and GPU than between the GPU and monitors. So go ahead and connect four 5K displays.
A 5K display is 28 Gbps (933 MHz x 30 bpp). Four of them is 112 Gbps. That is definitely not coming from PCIe or Thunderbolt.
The CPU tells the GPU to draw a line or copy a bitmap. The GPU makes the change in its VRAM. The GPU streams the VRAM contents to the display 60 times per second.
Mac mini (2018), Mac Pro (Early 2008), MacBook Pro (Retina, 15-inch, Mid 2015), GA-Z170X-Gaming 7, Sapphire Pulse Radeon RX 580 8GB GDDR5, Sonnet Echo Express III-D, Trebleet Thunderbolt 3 to NVMe M.2 case