Today we are looking at the ASRock Rack X470D4U2-2T. This is our second review in our coverage of ASRock Rack’s line of AMD Ryzen-based server motherboards. Previously we looked at the X470D4U, and while these two motherboards are very similar they do have some key differences. Since the market is so small for AMD Ryzen server platforms, and ASRock Rack is doing a lot of innovation here, we are going to give their second model a formal review.
ASRock Rack X470D4U2-2T Overview
The ASRock Rack X470D4U2-2T is a mATX motherboard measuring 9.6” x 9.6”. In that form factor, you get the AM4 socket which accepts Ryzen CPUs.
The official CPU support list starts at the Ryzen 2000 series and covers all the way to the top of the Ryzen 3000 series stack with support for the Ryzen 9 3950X. Officially, this list excludes the first-gen Ryzen 1000 series parts. We can confirm both the original Ryzen 5 1600 and the Ryzen 5 1600 AF CPU, which is derived from the Zen+ architecture used on the 2000 series CPUs, work without issue. With that information, it is likely the entire Ryzen 1000 line will work as well. Still, since it is technically unsupported, we wanted to present what we found for our readers.
Given the Ryzen CPU, there is dual-channel memory support for up to four DDR4 unbuffered DIMMs at speeds up to DDR4-3200. ECC memory support is included, and the relatively new 32GB ECC DDR4 2666 DIMMs are supported, giving a maximum memory capacity of 128GB.
During testing, one challenge was encountered with regards to the physical location of the CPU socket in relation to the memory slots. The Ryzen CPU being used for testing was installed with the stock cooler, specifically the AMD Wraith Stealth. This may not be the fanciest cooler, but those who are looking at this Ryzen-based solution for cost savings may want to use the boxed cooler to save additional expenditures.The first memory slot on the X470D4U2-2T is so close to the CPU socket that it is blocked from use while the Wraith Stealth cooler is installed. The fan on the cooler even makes light contact with the DIMM in the second memory slot.
A taller cooler like the Wraith PRISM would not have this problem, but other Ryzen coolers might encounter difficulty. Also, users with taller DIMMs than we tested with will certainly encounter problems with both slots 1 and 2. For typical server-style passive heatsinks this is not an issue. Still, for those looking to save money and making an inexpensive edge server (e.g. a NAS) with the stock cooler, this is an important challenge to consider.
Based on the AMD X470 chipset, this motherboard is limited to PCIe Gen3, even when populated by a Ryzen 3000 series CPU that would otherwise support Gen4. There are two PCIe x16 slots and an x1 slot. Only the first top x16 slot can operate at x16 link speeds. The second x16 slot is electrically x8, and if both x16 slots are occupied they automatically operate at x8/x8. In a difference from the X470D4U, which has an x8 (electrical x4) slot between the two x16 slots, the X470D4U2-2T only has a PCIe Gen2 x1 slot. In exchange for that lost slot, the PCIe Gen 3 x4 connectivity is used for the dual 10 GbE powered by the Intel X550-AT2 controller.
There are also two M.2 slots on board, but neither runs at the maximum PCIe 3.0 x4 speed as you might expect. M2_1 can operate at PCIe 3.0 x2 or SATA III, while M2_2 operates at PCIe 2.0 x4. If you want more PCIe connectivity, we suggest moving to AMD EPYC 3000 or EPYC 7000.
Additional storage is handled by the 6 onboard SATA III 6.0gbps ports provided by the AMD X470 chipset. This includes one port with support for SATA DOMs. Unlike the X470D4U, there is no Asmedia controller for an additional pair of SATA ports.
Rear I/O is limited; only two USB 3.0 ports are exposed. There is a serial port as well as a VGA output driven by the ASPEED AST2500. That AST2500 has its own dedicated NIC above the USB ports, and there are two 10GbE connections powered by an Intel X550-AT2 controller. This type of I/O layout is typical on a server board and is used to interface with the network and local KVM carts, but it is very different from what we see on consumer Ryzen platforms. This is a server platform, so it makes sense here.
That ASPEED AST2500 is the baseboard management controller and is one of the two defining features of this motherboard (the other being 10Gbase-T.) The BMC will allow out of band management of the system, full remote KVM, and mounting of virtual media over the network. Many of STH’s readers will be familiar with the ASPEED brand of BMC. ASPEED is commonly used on Inspur, Supermicro, Gigabyte, and other vendor boards. We also see them used in hyper-scale servers. An example is when we covered how Facebook Introduces Next-Gen Cooper Lake Intel Xeon Platforms. Its inclusion on a Ryzen board is very nearly unique at this point in time. If you need IPMI support from a Ryzen-based platform to be able to deploy and manage the server remotely, this ASRock Rack X470D4U2-2T is one of the only options around. Coupled with the front to rear chassis airflow, these are some of the changes made to turn a Ryzen platform into a server platform.
ASRock Rack X470D4U2-2T Topology
We wanted to take a quick moment here to show the system topology. We described it in words above but seeing it helps. First, here is the block diagram:
An explanation of that block diagram one can see in our hardware overview above. Here is the topology:
Since this is based on Ryzen, it is a single NUMA node design even when using Zen(+). AMD EPYC 7001 8-core servers, such as those based on the AMD EPYC 7251 had four NUMA nodes which created a lot of inter-die traffic. With Ryzen, one does not have to worry about that these lower-cost platforms.
Next, we are going to look at the CPU options, management, test configuration, and OS testing, before getting to performance and power consumption.