AMD EPYC 7351P Power Consumption
The other side of the equation is power consumption. The AMD EPYC 7351P is putting up some impressive benchmark numbers, but that does have an associated cost. Here is what we saw on our PDU after a few runs:
Idle power consumption was around 75W measured on the 208V PDU at 17.7C and 71% RH. Our testing window shown here had a +/- 0.3C and +/- 2% RH variance.
In terms of power consumption, and again this is without 24x NVMe drives installed, this is an idle result comparable to Xeon Silver. The maximum power consumption and what we are showing as a 70% load are both significantly higher than a single socket Xeon Silver or a dual Xeon Silver 4110 system by a wide margin. The dual Intel Xeon Silver 4110 setup will not hit above 200W running the same workloads as an example.
AMD is delivering a lot of performance in the sub $1000 segment. At the same time, that comes at the expense of power consumption. If you are saving $1000 on CPUs and systems and spending $15/ mo for another .12kW, that is a fairly easy TCO calculation to do.
As we pointed out in our dual AMD EPYC 7251 review, AMD has a number of competitive vectors. The obvious competition is the Intel Xeon single socket line. As a P series part, AMD is also positioning the CPU against lower-end dual Intel CPU configurations. We also see some competition from the dual AMD EPYC 7251 and the AMD EPYC CPUs around the same price range.
AMD EPYC 7351P v. Intel Xeon Silver
Since the AMD EPYC 7351P is a $750 part (although we are seeing street pricing slightly above that at the time of publishing around $820), it is not competing directly with Intel Gold CPUs, instead, it is competing with the Xeon Silver range. With the Intel Xeon Silver 4108 priced at just over $400, we see the EPYC 7351P priced as a significant competitor to that configuration. Likewise, the Intel Xeon Silver 4114 is a similarly priced single-socket Intel Xeon Silver option.
On the question of Intel Xeon Silver 1P and 2P configurations versus the 7351P, there are a few main points to consider. First, AMD flat out has more PCIe lanes with 128. Intel has 48 on the Intel Xeon Silver, although in dual socket configurations (96x) you could argue using a PCH does bestow some benefit in using those lanes efficiently. Second is memory capacity. The AMD EPYC 7351P can handle 16x DDR4-2666 DIMMs (8 channel) and up to 2TB of memory. Intel Xeon Silver can handle up to 12x DDR4-2400 DIMMs and 768GB of memory in single socket mode and twice that in dual socket configurations. Third is in terms of platform. Intel Xeon Scalable has more platform options available, and there are a few features that are more mature on the Xeon Scalable platform (e.g. NVMe hot-plug/ swap and QuickAssist) that AMD platforms still have to catch-up on in terms of ecosystem maturity.
If you run Dockerized microservices and are not leveraging features such as QAT, EPYC simply has Intel Xeon Silver beat. Likewise, as in the case with this Tyan test system, AMD having more PCIe lanes makes a compelling argument. It is not that Intel does not have parts that compete with AMD. Intel’s product segmentation including features and pricing where features like dual AVX-512 are not present on low-end SKUs, DDR4-2666 and higher memory capacities are not supported on Xeon Silver. Omni-Path is not supported on Xeon Silver (as on package fabric.) In terms of volume, the Intel Xeon Bronze and Silver are low value but high volume parts and Intel needs to do some soul-searching. Intel Xeon Silver does have better power consumption characteristics which is important yet we have seen IT buyers accept higher power consumption for higher performance.
What AMD essentially did with the EPYC 7351P is put forward a high-performance offering in a price segment where Intel is geared specifically for low power use. To be clear, Intel does have high-performance chips. The sub $1000 CPU segment for Intel is focused solely on low power consumption, not performance.
In 2017/ 2018 it may be enough that Intel is Intel and has commanded huge market share for years. In upcoming generations, that is going to be a harder sell. Either way, if you have a dev ops team EPYC should be a part of this year’s server purchases.
AMD EPYC 7351P v. AMD EPYC
In the x86 market, the AMD EPYC 7351P is not just competing against Intel, but also other SKUs in the AMD stack. Two AMD EPYC 7251’s are slightly more than a single AMD EPYC 7351P. The ability to use more memory per system or more lower capacity and less costly DIMMs may make that a compelling solution for buyers.
Unlike many of the other SKUs, as a “P” series part, the AMD EPYC 7351P sits between the EPYC 7281 and EPYC 7301 pricing wise. For us, the choice is clear, if you are using a single socket system, get the P series EPYC parts in that price range. A good debate when purchasing this is whether or not to move up to the EPYC 7401P since one gets 50% more cores at slightly lower clock speeds for a relatively small price premium. We are going to have more on that soon, but essentially moving one “P” part up the stack pits a $1075 AMD CPU with 24 cores against the 12 core Xeon Silver 4116 at around $1020. While Intel may have some IPC advantages in some workloads, the de-featuring of the Xeon Silver line makes AMD’s offerings really shine even more so than we are already seeing with the EPYC 7351P.
At STH, our first introduction to AMD EPYC was the dual EPYC 7601 configuration. Our test system originally had an AMD EPYC 7601 installed and we were planning on first publishing 1P 7601 results. As we worked through various other configurations, it became clear that while AMD is very competitive at the high-end, its mainstream offerings are competing with de-featured Xeon Silver CPUs and absolutely obliterate what Intel is offering. Addressing the obvious, one has to be willing to be different at their job and deviate from purchasing Intel x86 to buy AMD instead. Here one can take solace in the fact that the AMD EPYC 7351P is not marginally better than the Intel Xeon Silver single (and low-end dual) socket offerings, but instead, there is an enormous chasm created by Intel’s conservative product offerings in the Xeon Silver space versus AMD’s aggressive moves in the mainstream market with the EPYC 7351P. While the EPYC 7351P looks impressive compared to Xeon Silver, we are soon going to show the EPYC 7401(P) numbers that will make you pause.
We also run our own hosting cluster that is currently all Intel-based. AMD EPYC platform maturity and our experience with the Tyan Transport SX TN70A-B8026 thus far means we will be adding AMD EPYC in the next round of upgrades in Q4 2017/ Q1 2018. AMD systems and CPUs are starting to hit the channel for smaller buyers like us. We now have systems from several different vendors already up and running in the lab and the overall platform maturity has come a long way since June.