E-ATX format, 9 PCIe slots and 16 cm silent fans for workstations with up to two RTX 5090: this is the FSP U661

E-ATX format, 9 PCIe slots and 16 cm silent fans for workstations with up to two RTX 5090: this is the FSP U661

During Computex 2026, at the FSPwe have been able to see the U661an E-ATX chassis aimed at workstation, but with a somewhat different speech than the U500. If that one relied more on the extreme of liquid cooling and the dual GPU format, here the brand puts more emphasis on air flow, contained noise and a design prepared for very heavy cards without complicating assembly too much.

Specification U661
Format E-ATX Air Flow Workstation
GPU support Transit-Safe GPU Holder
Fans Large 16cm silent fans
PCIe slots 9
Featured Compatibility Up to dual RTX 5090
Storage Up to 4 HDD + 1 SSD
Color Black

An air workstation designed for very heavy graphics

The U661 makes its terrain quite clear from the file itself: 9 PCIe slotsTransit-Safe support and compatibility with double RTX 5090. That already places it in a segment where the problem is not only putting in a lot of hardware, but also ensuring that the weight of the cards does not end up generating undue stress during use or transport. FSP tries to answer that with its GPU-specific support system.

The other important point is in the fans. 16cmwhich the brand sells as a high-flow silent solution. It is a different strategy than a box more focused on huge radiators: here the focus is on moving a lot of air with less noise and with a more direct architecture for a high-flow workstation.

Seen at the stand, the U661 fits as a quite logical alternative for those who want a powerful station chassis, but not necessarily as focused on liquid as other proposals in the same catalog. His message is simpler: space, GPU support, plenty of air and less noise. And for some of the professional market, that’s probably more useful than any visual addition.