The ASUS RS521A-E12-RS12U is a 2U rackmount server built to offer a hybrid of CPU and GPU compute as well as built-in storage capabilities. It utilizes an AMD EPYC 9004 Series processor, which supports a massive 128 PCI-Express Gen 5 lanes as well as 12 DDR5 memory channels - ensuring plenty of bandwidth and connectivity for running up to two dual-slot graphics cards and several NVMe solid-state drives.
Storage options include two internal M.2 slots for SSDs, twelve front-accessible hot-swap bays which support U.2 NVMe SSDs, SATA drives, and even SAS (with an optional controller card), and two additional rear 2.5-inch bays supporting SATA SSDs. We recommend putting the OS on one of the M.2 slots and then using the easy-access bays in the front and rear for storage as needed.
External connectivity consists of four USB ports (2 each in front and back), two Gb LAN ports, and another LAN for remote management. There are options for additional networking via both an OCP 3.0 slot and a half-height PCIe slot. That PCIe slot can also be used for a SAS controller if desired.
Storage options include two internal M.2 slots for SSDs, twelve front-accessible hot-swap bays which support U.2 NVMe SSDs, SATA drives, and even SAS (with an optional controller card), and two additional rear 2.5-inch bays supporting SATA SSDs. We recommend putting the OS on one of the M.2 slots and then using the easy-access bays in the front and rear for storage as needed.
External connectivity consists of four USB ports (2 each in front and back), two Gb LAN ports, and another LAN for remote management. There are options for additional networking via both an OCP 3.0 slot and a half-height PCIe slot. That PCIe slot can also be used for a SAS controller if desired.
Model: Asus RS521A-E12-RS12U-20TW1G
Specifications
| Socket | SP5 |
| CPU Compatibility | AMD EPYC 9005 series (up to 400W) |
| Form Factor | 2U |
| Chipset Manufacturer | AMD |
| Network Connectivity | Dual Gigabit Networking |
| Network Controller | Intel I350-AM2 |
| Cooling System | Heatsink and Fan |
| Number of Fans | 8 |
| Color | Black |
| Windows Support | Windows Server 2025 |
| Linux Support | Yes |
Memory Support | |
| Type | DDR5 ECC Registered |
| Maximum Speed | 5200 MHz |
| Number of Slots | 24 |
| Maximum Size per Slot | 96 GB |
| Maximum Amount Supported | 2304 GB |
Onboard Video | |
| Chipset Manufacturer | ASpeed |
| Processor Type | AST2600 |
| VGA | 1 |
External Connections | |
| USB 2.0 | 2 |
| USB 3.2 Gen 1 (USB 3.0) | 2 |
| LAN (RJ45) | 2 |
| Mgmt LAN (RJ45) | 1 |
| BIOS Flashback | No |
Internal Connections | |
| M.2 Connector | 2 |
| M.2 Support | 2x 42-110mm PCIe 5.0 |
| TPM (module sold separately) | 1 |
| Compatible TPM | Asus TPM-SPI |
Expansion Slots | |
| Slot 1 | PCI Express 5.0 x16 |
| Slot 2 | PCI Express 5.0 x16 |
| Slot 3 | PCI Express 5.0 x8 |
Additional Information | |
| Remote Management | Onboard |
| Includes Rail Kit | Yes |
| Hearing Protection Advised | Yes |
BIOS Features | |
| UEFI BIOS | No |
| EZ Flash | No |
| OC Profiles | No |
Dimensions | |
| Height | 88.1 mm (3.5 in) |
| Width | 449 mm (17.7 in) |
| Depth | 840 mm (33.1 in) |
| Net Weight | 17.95 kg (39.6 lbs) |
Power Supply | |
| Input Voltage | 100-240 Vac |
| Wattage at 120V | 2600 W |
| Wattage at 240V | 2600 W |
| Redundancy | 1+1 |
Expansion Slots
Up to 5 PCIe Gen5 slots + 1 OCP3.0
2 x PCIe Gen5 x16, FHFL or 4 x PCIe Gen5 x8, FHFL
1 x PCIe Gen5 x8, LP
1 x OCP 3.0 Slot ( (PCIe Gen5 x16)
