Best workstation motherboards for multi-GPU AI builds

Top pick: ASRock WRX90 WS EVO. For a multi-GPU AI box it's the most straightforward choice — Threadripper PRO 7000WX on sTR5, a big EEB board with the PCIe lane count and memory headroom that four GPUs and large models actually need.

Who the others suit:

• ASUS Pro WS WRX80E-SAGE SE WIFI II — same idea on the older WRX80 platform; pick it if you already have a Threadripper PRO 3000WX/5000WX CPU or want proven 7-slot layouts.
• Gigabyte MC62-G40 — Threadripper PRO 5000WX, CEB form factor; a solid mid-generation workstation base.
• Gigabyte MZF2-AC0 — dual EPYC server board built around four GPUs; best when you want maximum cards per box and don't mind server-style DDR4 RDIMMs and a rack chassis.
• ASRock EPYC SP3 board — single-socket EPYC with huge lane counts; suits a dense, quiet-ish tower build.
• ASUS Pro WS W680 ACE — the budget-conscious route for two cards on Intel LGA1700; fewer lanes, so plan slot spacing carefully.

Skip the consumer X870E/B550 and the X79 bundle: not enough x16 lanes for real multi-GPU work.