Thunderbolt bandwidth requirements \ limitations for multiple high resolution di...
 
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[Solved] Thunderbolt bandwidth requirements \ limitations for multiple high resolution displays  

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LukeAtWork
(@lukeatwork)
New Member
Joined: 5 months ago
 

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.

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joevt
(@joevt)
Noble Member
Joined: 4 years ago
 

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), GA-Z170X-Gaming 7, Sapphire Pulse Radeon RX 580 8GB GDDR5, Radeon Pro W5700, Sonnet Echo Express III-D, Trebleet Thunderbolt 3 to NVMe M.2 case


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