Chips · Oct 19, 2026, 14:28
AMD Helios Switch Tray Uses Two Tomahawk 6 Chips for 224G Scale-Up
HPE Juniper's QFX5252 tray for AMD Helios uses two liquid-cooled Tomahawk 6 switches and retimers to drive 224G PAM4 scale-up links inside the rack.
Liquid cooling and copper cabling at the back of an AI rack.
Illustration (AI-generated)
OCP 2026, Oct. 15 — HPE showed the open switch tray built for AMD's Helios AI rack on the OCP 2026 show floor, revealing a double-wide, liquid-cooled HPE Juniper QFX5252 that carries two Broadcom Tomahawk 6 chips to run the rack's 224G PAM4 scale-up fabric.
The Technical Details
The QFX5252 is not a front-panel switch. It is a 1OU, double-wide tray that blind-mates into the rear of the Helios rack, where high-density fabric connectors feed cable cartridges that link the accelerators. ServeTheHome reports the rear connection count is high enough that the tray needs unusually long latch levers to overcome insertion force.
Broadcom's Tomahawk Ultra, the part aimed at scale-up Ethernet, tops out at 112G PAM4 lanes. Helios signals at 224G per lane, so AMD and HPE Juniper moved to Tomahawk 6. Liquid-cooled blocks sitting between the switch chips and the far rear connectors are reported to be retimers.
- Tray: HPE Juniper QFX5252, double-wide, 1OU
- Switch silicon: 2x Broadcom Tomahawk 6
- Helios lane rate: 224G PAM4 SerDes
