2015 Gigabyte X99 Designare [5th,6C,K] + R9 Fury X @ 32Gbps-TB3 (Sonnet Breakaway 350) + Win10 [itsage]
Gigabyte GA-X99 Designare EX Motherboard - i7-5820K/Radeon RX 480 dGPU/8GB RAM/480GB SATA SSD
To be updated with current photos. Here's one from last year with another Gigabyte motherboard (Z170 Ultra Gaming) that has built-in Thunderbolt 3 connectivity.
Thanks to @Yukikaze who suggested our community should have a test bench to figure out the main culprit of TB3 performance loss, I have been maintaining this setup for when the needs arise. My local Microcenter was clearing out X99 equipment and this Gigabyte X99 Designare board was less than $100. It's packed with features but the most important one is the direct routing of Thunderbolt 3 connection to the CPU. Also worth mentioning is a PLX switch that enables a 24-lane CPU such as the i7-5820K run triple CrossFire at x16 3.0 each.
I had attempted pairing an eGPU with this same motherboard last year but was not able to overcome error 12. Gigabyte has since updated the BIOS. I'm not sure if the newer BIOS helps or I have more patience this time but I'm now able to use both Nvidia and AMD eGPU with the X99-Designare. The key is to choose the right settings in the BIOS. By default Thunderbolt Boot Support and Thunderbolt eGFX Support are Disabled. You want both of these Enabled. Hot-plugging would always produce error 12. Boot up with the eGPU attached is the only way I was able to overcome error 12 so far. Here are a couple of screen captures in the BIOS settings.
Another common issue is outdated USB-C firmware. When this motherboard was released, Gigabyte didn't have Thunderbolt 3 certification. Therefore the firmware was USB-C only. If you plug a TB3 eGPU in, it would power up but would not work. Here's the Thunderbolt firmware utility to update the built-in Thunderbolt 3 functionality. I've tried a mixed of enclosures and they all working as expected. Once Thunderbolt eGFX Support is enabled, Intel Thunderbolt Software shows External GPUs Supported: Yes.
My next attempt is to get the eGPU going with the three dGPUs in place. At the moment it's not reliable. The eGPU would cause boot issues with more than one installed dGPU. The one successful boot up resulted in error 12 with a Vega Frontier eGPU.
Something else I wanted to do was running a TB3 add-in card so that I could have both TB3«»PCH and TB3«»CPU on this same test bench. I have not been able to get a Gigabyte ALPINE RIDGE card and settled for an ASUS ThunderboltEX 3. Little did I know the Thunderbolt 3 header connectors (TB_HEADER on the motherboard) of these two add-in cards are different. They are not interchangeable without great efforts (pointy nose plier and electrical tape). While they both have 5-pin connectors and look alike, the spacing between the metal pins are not the same. This, my friends is why Thunderbolt will continue to struggle for mainstream adoption.
@john_petrucci I'd say it won't work. If you use a 550W PSU in the Breakaway Box 350 my guess is it would work with both Vega 56 and 64. The firmware on the Breakaway Box 350 limits Power Delivery to only 15W, reserving much of the PSU output to the GPU.
Did you get around to testing the difference between pch and direct cpu link for egpu performance? Currently interested as the upcoming ice lake cpus have the thunderbolt cicuitry embedded in the cpu.
Do you think the ice lake laptops will be a leap forward for the egpu community? Or provide no tangible difference, other than minor efficiency/cpu performance improvements?