AMD EPYC 3251 vs Xeon D-2143! Review of the ASRockRack EPYC3251D4I-2T mini-ITX motherboard

I was really looking forward to testing the AMD EPYC 3000, and here’s why: the EPYC 7000 series processors, both on the first - generation core (Naples) and the second-generation core (Rome), are a real hit and a breakthrough in the world of cloud computing and virtualization. But not a single cloud lives a person, and for dedicated network gateways, NAS-s, various security systems or for peripheral computing, 32 cores-a clear bust. In such tasks, rarely anyone loads more than 4 cores, and compactness and the ability to work well, literally under the feet of the sysadmin, and not in a room with air conditioning - are qualities for which customers pay money. Intel has a wonderful Xeon D processor for these tasks, on which you can produce just freaky compact, but very powerful motherboards of the Mini-ITX format. There are 16 threads, and 10GBASE-T Ethernet controllers, and Oculink ports for SATA or PCI-E drives, and M. 2 slots: well, just everything you need for Edge Computing.

And if Intel is in a very advantageous situation, could do such a miracle as Xeon D, all AMD need is just to cut off the single crystal from chiplet your EPYC 7000, solder the legs to it - and get EPYC 3251: the same 16 threads, same SoC, only this processor was born in a family where the word “security” is not an empty phrase, but means you are not afraid of the attack on the microcode and medicines from them, slowing down the speed of the host.

Specification Xeon D-2143IT EPYC 3251
Number of Cores 8 8
Number of Threads 16 16
Lithography, nM 14 14
L2 Cache, Mb 4
L3 Cache, Mb 11 (L2+L3) 16
TDP, Wt 65 55
Base Frequency, GHz 2.2 2.5
Turbo Frequency, GHz 3.0 3.1
Memory subsystem
Number of memory Channels 4 2
Max. Frequency of DRAM, MHz 2133 2666

We have a motherboard that reveals the whole essence of an integrated processor with TDP 55 Wt. In the Mini-ITX format, the ASRockrack EPYC3251D4I-2T model has a pair of 10-Gigabit copper interfaces, supports up to 256 GB of RAM, and on conventional RDIMM modules, and not on expensive LRDIMM. If you want to save even more, you can use desktop “non-ECC” memory.

As you can see, in the RAM area, the differences between the EPYC 3251 and the Xeon D-2143 are very significant: AMD has fewer channels, but higher frequency, plus the ability to use desktop RAM.

Network Subsystem

ASRockRack has not indulged customers with a large number of network ports for a long time, believing that the built-in 20 gigabits/s will be enough for any needs. In addition, using these ports in out-of-band mode, you can access the IPMI interface of the motherboard, if for some reason you do not want to use a dedicated network port. Interestingly, a separate Intel X550-T2 controller is used for the network, rather than a built-in AMD processor. This should increase compatibility with capricious software, especially in features like SR-IOV.

The network controller supports PXE, and the first LAN port supports NCSI. In the Arsenal of ASRockrack there are analogues of this Board with a 1-Gigabit network on the Intel i350 chip. As a rule, in boards with this controller there is a loading on iSCSI which at all is absent in 10-Gigabit variants. We recommend our review: Aquantia AQC107 vs Intel X550-T2 to get acquainted with the network adapter integrated on this motherboard.

Storage subsystem

For compact cases, which ASRockrack EPYC3251D4I-2T is designed for, there are plenty of features: 2 SATA-600 ports, one M.2 22110 (PCI - E 4x Gen3) and one Oculink, switchable to 4 SATA or 1 PCI-E (Gen3 4x). When you install a drive slot with SATA 3 interface in M.2, one of the SATA ports will be disabled, so there is no sense in this. That is, if you need more space - you can connect 6 hard drives + cache M.2 SSD PCI-E, if more speed-M.2 or PCI-E SSD. There is no hardware RAID on the board, so if you need something more-use a PCI-E controller.

The AMD EPYC 3251 processor itself supports 32 PCI-E Gen3 lines, and this number is enough to output a full PCI-E 16x slot that does not share the bus with anything, so even if you have completed the motherboard as much as possible, you can use the GPU or interface controller.

Additional connections

Additional pins include pads for connecting SATA SGPIO, COM1 port, TPM module, and two USB 3.1 ports.

In addition, there are pins for connecting IPMB and PSU SMBus monitoring buses.

Cooling and powering

Despite the fact that the EPYC 3251 processor is considered energy-efficient by modern standards, its power is up to 55 W, and for this value you need a good active cooling. However, only a passive aluminum radiator is installed on the board, and the instructions say that if the air flow through it is below 2 CFM, then you need to install a fan. Without additional cooling, just lying on the table in the BIOS (when all the energy-saving features are turned off), the processor easily warms up to 97 degrees, and no matter how scary it looks, the critical temperature for it is 105 degrees Celsius. And yet the designers were right: the processor doesn’t need much, and the slowest fan easily resets the temperature to 56 degrees in boot mode.

In accordance with modern trends in the design of the boards, only 3 aluminum solid-state capacitors are installed here, and IC elements located on the back side of the motherboard are mainly used for power filtration. Connectors for connecting fans have an led indication of the fault of the cooler - a nice and damn convenient addition.

The board uses an interesting circuit connection to the power supply: well, first, so as not to waste precious space Mini-ITX format, the power input is 4-pin + 8 pin, and comes with an adapter with ATX 24 pin to ATX12V 4 pin. Secondly, if your power supply does not have SATA ports, then you can take power directly from the motherboard through an unusual cable with ATX12V 4 pin to SATA. Why do the input and output power on the motherboard is absolutely identical, you are unlikely to tell anyone, but they will warn you that the wrong connection of cables leads to the imminent death of the board.

Remote controlling IPMI/BMC

For remote control, the ASPeed AST2500 chip is used with a dedicated 1-Gigabit network port, which is only used for BMC functions and nothing more. I would like to say that AST 2500 is the best solution to date, having a modern HTML5 interface optimized for tablets and smartphones. You can use fast and convenient console management, connect a remote disk to install the operating system both from your computer and through the NAS. There is a very convenient temperature monitoring and the ability to record POST-tests.

Compared to the Dell iDRAC, HPE iLO and Lenovo XClarity management systems, you don't pay for remote management, but get almost the same features, not to mention the fact that you can simply forget about IP-KVM like a bad dream. Yes, and yet: if you do not use a dedicated Gigabit network port, you can access the BMC through a 10-Gigabit port: the Board has a kind of network switch, so that one network wire we can go to the web interface of the hypervisor, and the BIOS through the console. Cool!


Among the interesting features of the AMI BIOS should be noted non-switchable timer Watch Dog, which has 2 modes of server reboot: Reset and NMI, the choice of operating mode for Oculink SATA port, as well as the ability to configure the thermal package of the processor and access to AMD Zen, which is usually in the server motherboards you will not find.


And in general, the BIOS is seriously distinguished by its equipment among the gray mass: here you have a full-fledged hardware monitoring, and configuration of memory controllers and PCI Express… Those who like to dig into the parameters will be satisfied.

Compatibility question (VMware, FreeNAS)

The weak point of the motherboard in question is the lack of declared compatibility with VMWare ESXi and FreeBSD. The latter is seriously depressing, since the most common free security gateways (PFSense, OPNSense) use a “FreeBSD” kernel, and where there are compatibility problems-they are run under ESXi. Well, that is, though stand, though fall, but in the list of supported OS only 64-bit RHEL / Centos, Ubuntu and Windows Server 2016. I asked a friend of mine, a VMWare representative, when ESXi would support EPYC 3000, but he said that he did not know and refused to comment at all, although he is usually very talkative. And although from my point of view it is absolute nonsense to get hung up on one processor manufacturer, yet VMware can understand: they need to sell their hypervisor in expensive cloud environments, and the EPYC 3000 is not their caliber.

I could not pass by such a challenge and check on my experience what and how it works, and the first thing I did was to install VMware ESXi 6.7 U3 from scratch on our test motherboard. Everything was established without a hitch, as if it should be, and after playing with the launch of their virtual machines, I decided to check whether the EPYC 3000 is ready to fit into the AMD ecosystem? In our article “Switching from Intel Xeon to AMD EPYC: debunking myths, avoiding pitfalls” we touched on the lack of live migration between Intel and AMD, but now I have a server under my desk on EPYC 7551p, and on the table - unsupported EPYC 3251. What do you think?

Running Linux Mint perfectly moved without stopping. That is, here are some technical issues related to poor support for APIC 3000 from VMware is not present, and perhaps they are with AMD just could not agree on certification issues. Moreover, I ran all our tests under ESXi 6.7 U3, and the only point that I noticed is the “penalty for virtualization” in synthetic tests. For example, running on" bare metal" Cinebench R15 gives 25% more speed than with the same parameters, but in virtualka. The Xeon and EPYC 7000 have a much lower figure, about 10%, so if VMware optimizes for EPYC 3000, it will probably work even faster.

Just as easily and simply earned FreeNAS 11.2, being installed on bare metal. I have already mentioned in other articles that some widely supported community distributions of FreeBSD work fine on AMD EPYC, although the official support for “Red ones” is stuck somewhere at the level of Athlon 64.

In summary, if you need to integrate AMD EPYC 3000 into the EPYC 7000 ecosystem, these processors are compatible with each other: you will have live migration and support in the virtual environment of any OS. Even ESXi works like a clock, although it does not openly admit it.


Test bench configuration:


  • VMware ESXi 6.7 Update 3
  • Windows 10 x64, Oracle Linux 7
  • 16 vCPU, 16 Gb RAM
  • Memory: 2x16 Gb Transcend DDR4-2400 ECC RDIMM for EPYC 3251 and 4x16 Gb Kingston DDR4-2133 ECC RDIMM for Xeon D-2143

Please note: we have a 2-channel memory configuration in the AMD stand and a 4-channel memory configuration in the Intel stand to fully load the processor capabilities. Before we go directly to the tests, let’s look at the CPU-z output.


Now let’s go through the synthetic tests from under the guest Windows 10, remembering that the penalty for virtualization on EPIC 3251 is higher than on Xeon 2143.

Our old Xeon E5-2603 V4 got mixed up in the test results clearly by mistake, but the first benchmark showed that a serious test is being prepared for Xeon here. AIDA64 will show performance in more detail.


Well, just excellent encryption speed and failed results in photo processing. Do not forget that this is just Windows 10 and full synthetics, in fact, everything can be different, and the first real test, non-relational database Redis, says that in relation to Xeon D 2143 is just “beating babies”. Here it is likely that the Xeon D 2143 is worse at increasing the core frequency at boot, because I do not see any other explanation for the 1.5-fold difference in favor of AMD.


But it is necessary to consider that Redis at Set/Get operations strongly depends on memory speed and to a lesser extent on some internal architecture of the processor. Quite another thing is MySQL databases, where we create a table with 1 million rows for testing, and run the test on 100 thousand rows, because in multithreaded mode, these processors do not need more. As a measure, we use the delay, which should ideally be less than 20 ms.

En_tests_6 En_tests_7

The results of this test speak for themselves: the EPYC 3251 is on average 2 times faster than the Xeon D 2143IT.


According to the power consumption of the Board with 1 RDIMM module, we can say that on average, the EPYC 3251 will be twice as slow to wind the counter than the Xeon D-2143IT.


Our tests show that the EPYC 3251 in real applications is twice as fast as the Xeon D-2143, and at the same time consumes 2 times less electricity, which means less heat and does not require any special cooling. With these features, it is better suited for a peripheral computing server or for use as a small company virtualization node that hosts a gateway, NAS, and domain controller. Two-channel memory controller is not a reason to be sad, because with 4-channel Xeon works slower, and the only thing to worry about is the software. Officially you only have Windows + Linux, but unofficially you can use VMware ESXi and FreeBSD.

On average, the considered motherboard based on EPYC 3251 will cost the customer 700-800$, while the option based on Xeon D 2143-about 1200-1300$. The difference in price between the platforms is also true for the products of other vendors, so even from the point of view of the EPYC 3000 wallet is beautiful!

Choosing a motherboard on EPYC 3251, pay attention to the board we are considering from ASRock Rack: the Intel X550-T2 network controller is the best that exists today for 10-Gigabit copper. Connections to DC12V power supplies - this is the ability to power the control PC from the on-Board network or batteries, bypassing the inverter. The silent 120-mm fan that blows the motherboard reduces the CPU temperature in Idle mode to 25 degrees Celsius, and in the BIOS you can set the maximum TDP to reduce the maximum temperature, for example in the blade-case on the Mini-ITX platform.

We recommend ASRockRack EPYC3251D4I-2T for use in security gateways, NASes and “Edge servers”, that is, where you should have Xeon D or initial versions of Xeon E5.

VMware seems to be allowing all EPYC processors to run their products. I have an EPYC3251 server and I found that I had to edit some files to get VMware NXS-T 2.5 to run properly. In version 3.0 of NSX-T the code explicitly allows AMD EPYC CPUs and not other AMD CPUs.

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This is quite normal, because historically, VMware only supported server processors.