Gigabyte MZ33-AR1: A Uniquely Positioned AMD EPYC 9005 Motherboard For Open-Source Firmware
👁 Gigabyte MZ33-AR1 server build
The Gigabyte MZ33-AR1 is an E-ATX motherboard supporting both EPYC 9004 and EPYC 9005 series, 12 channel DDR5 RDIMM support with 24 DIMMs for two DIMMs per channel, four PCIe Gen5 x16 slots, dual 10 Gigabit Ethernet via a Broadcom BCM57416 chipset, five MCIO connectors on PCIe Gen5 and one MCIO connector on PCIe Gen4, and all around a nicely equipped EPYC Turin 1P motherboard design for those building their own EPYC server.
👁 Gigabyte MZ33-AR1 BMC interface
Unlike some of the EPYC 9005 1P motherboards we have looked at in the past like the Supermicro H13SSL-N that topped out at 400 Watt CPU support, the Gigabyte MZ33-AR1 does support up to a 500 Watt TDP CPU so the entire EPYC 9005 series is compatible. Going up to 128-core EPYC 9755 or 192-core EPYC 9965 processors works completely fine on this motherboard.
On the downside, my biggest complaint about this motherboard is that it only supports up to DDR5-5200 even at one DIMM per channel. Rather than DDR5-6000 / DDR5-6400 with most of the other EPYC 9005 motherboards, the Gigabyte MZ33-AR1 can only operate at DDR5-5200 or it drops to DDR5-4400 when running at 1R 2DPC or DDR5-4800 at 2R 2DPC. When buying this motherboard for the 3mdeb firmware focus, I hadn't looked into the memory specs but bought this board solely for the Coreboot+openSIL future. So after assembling the server and wondering why I wasn't able to run above DDR5-5200 and going through BIOS/firmware upgrades and more did I then realize the motherboard's limitation. (Update: This DDR5-5200 limit looks like it may be a platform limitation of all EPYC Turin motherboards having 24 DIMMs on the motherboard, irregarless of populating just 12 DIMMs.)
👁 Gigabyte MZ33-AR1 MegaRAC SP-X
Depending upon your storage plans, another item to point out with the MZ33-AR1 is that the sole M.2 slot on this motherboard only operates at PCIe Gen4. If you are planning to use PCIe Gen5 storage you will either need to be connecting via an adapter with one of the four PCIe Gen5 x16 slots or using one of the PCIe Gen5 MCIO connectors to your PCIe Gen5 storage device.
👁 Gigabyte MZ33-AR1 remote viewer from BMC
The MegaRAC SP-X BMC firmware stack did work out well for what shipped on the motherboard, complete with the remote HTML5 viewer. Of course, I am eager to see OpenBMC on this board thanks to the work being done by 3mdeb.
👁 Gigabyte MZ33-AR1 with liquid cooling
Besides those caveats, the Gigabyte MZ33-AR1 has been working out quite well in my testing thus far. Using the EPYC 9755 500 Watt CPU, full 12 x DDR5 RDIMMs, and various Linux distribution releases have all worked out well on this Gigabyte EPYC 9005 1P motherboard. The performance was right inline with other EPYC Turin retail motherboards except for memory bound workloads due to the reduced DDR5-5200 speed.
👁 Gigabyte MZ33-AR1 server build complete
At around $700 USD (or around $800 at some Internet vendors), the price is similar to the other most affordable EPYC 9005 1P motherboards with it being difficult to find options much cheaper than that in the current economic environment. On its own the Gigabyte MZ33-AR1 is a nice EPYC 9005 Turin motherboard with a robust feature set but with the main gripe being the DDR5-5200 support rather than DDR5-6000/6400. But thanks to the independent work of 3mdeb on bringing Dasharo/Coreboot to it atop AMD openSIL, it's very interesting and the de facto winner for those interested in exploring AMD open-source firmware support on current-generation AMD EPYC servers. Stay tuned for much more on that side in the weeks ahead.
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