YouTuber Der8auer Showed off A pair of new AMD AM5-based B665 workstation motherboards feature a 90-degree socket orientation, designed for improved airflow and better compatibility with server-based CPU coolers and chassis. The two new boards are the Asus Pro WS B665-ACE and the Asrock Rack B665 D4U1L.
I don’t know anything about this new B665 socket, and I don’t know much about these new boards in general. But Der8auer says these are value-oriented workstation motherboards with minimal features. At least we know it will support AMD’s 65W Ryzen 7000 series CPUs.
Based on images of both motherboards, it appears to be a cut-down version of the B650 chipset motherboard. The rear I/O has been slashed to save costs and his VGA port has been added for the server. Both boards cut PCIe connections from Gen 5 to Gen 4, but Der8auer says this is a board-specific limitation to reduce cost, not a chipset limitation. The Asus board is his ATX solution, while the ASRock board is a micro-ATX solution.
The most unique thing about both boards is the 90 degree orientation of the AM5 socket, which is common only in server and workstation platforms like the Xeon W3400 series and Threadripper Pro.
The 90-degree orientation is uncommon in consumer platforms, but it’s very convenient for the server cooling solutions and chassis most of these boards are likely to be in. The 90-degree rotation means you can use server-class elongated heatsinks, with fins that extend a few millimeters further out than standard coolers. This allows the air to stay inside the heatsink fins longer and extract more heat from the fin stack, lowering the temperature by a few degrees Celsius.
Another cooling effect of the 90 degree rotation is that the DDR5 DIMM slots can be relocated from the side of the board to the top. This also improves cooling of the DDR5 memory by opening the airflow from the chassis air intake to the CPU heatsink, allowing the air to pass vertically through the module gaps instead of horizontally.
Der8auer demonstrated this capability using an Asus B665 board housed inside a Hetzner AX52 server rackmount chassis. The 90-degree orientation allowed the use of elongated server heatsinks, and the rear exhaust fans were able to pull air completely directly onto the heatsink fins. If you’re unfamiliar with rackmount servers, the chassishe fan is designed to cool both the chassis and the heatsink itself. Eliminates the need for dedicated chassis and CPU cooling fans.
This type of cooling metering is ideal for systems utilizing these consumer-based workstation motherboards. Motherboard manufacturers have been producing workstation motherboards for Intel and AMD consumer platforms for years as an alternative solution to more expensive dedicated server hardware. This is ideal for small workstation or server applications that don’t necessarily need all the features or horsepower of a Xeon or AMD EPYC processor.
