Sizing Up Servers: Intel's Skylake-SP Xeon versus AMD's EPYC 7000 - The Server CPU Battle of the Decade?
by Johan De Gelas & Ian Cutress on July 11, 2017 12:15 PM EST- Posted in
- CPUs
- AMD
- Intel
- Xeon
- Enterprise
- Skylake
- Zen
- Naples
- Skylake-SP
- EPYC
Closing Thoughts
First of all, we have to emphasize that we were only able to spend about a week on the AMD server, and about two weeks on the Intel system. With the complexity of both server hardware and especially server software, that is very little time. There is still a lot to test and tune, but the general picture is clear.
We can continue to talk about Intel's excellent mesh topology and AMD strong new Zen architecture, but at the end of the day, the "how" will not matter to infrastructure professionals. Depending on your situation, performance, performance-per-watt, and/or performance-per-dollar are what matters.
The current Intel pricing draws the first line. If performance-per-dollar matters to you, AMD's EPYC pricing is very competitive for a wide range of software applications. With the exception of database software and vectorizable HPC code, AMD's EPYC 7601 ($4200) offers slightly less or slightly better performance than Intel's Xeon 8176 ($8000+). However the real competitor is probably the Xeon 8160, which has 4 (-14%) fewer cores and slightly lower turbo clocks (-100 or -200 MHz). We expect that this CPU will likely offer 15% lower performance, and yet it still costs about $500 more ($4700) than the best EPYC. Of course, everything will depend on the final server system price, but it looks like AMD's new EPYC will put some serious performance-per-dollar pressure on the Intel line.
The Intel chip is indeed able to scale up in 8 sockets systems, but frankly that market is shrinking fast, and dual socket buyers could not care less.
Meanwhile, although we have yet to test it, AMD's single socket offering looks even more attractive. We estimate that a single EPYC 7551P would indeed outperform many of the dual Silver Xeon solutions. Overall the single-socket EPYC gives you about 8 cores more at similar clockspeeds than the 2P Intel, and AMD doesn't require explicit cross socket communication - the server board gets simpler and thus cheaper. For price conscious server buyers, this is an excellent option.
However, if your software is expensive, everything changes. In that case, you care less about the heavy price tags of the Platinum Xeons. For those scenarios, Intel's Skylake-EP Xeons deliver the highest single threaded performance (courtesy of the 3.8 GHz turbo clock), high throughput without much (hardware) tuning, and server managers get the reassurance of Intel's reliable track record. And if you use expensive HPC software, you will probably get the benefits of Intel's beefy AVX 2.0 and/or AVX-512 implementations.
The second consideration is the type of buyer. It is clear that you have to tune more and work harder to get the best performance out of AMD EPYC CPUs. In many ways it is basically a "virtual octal socket" solution. For enterprises with a small infrastructure crew and server hardware on premise, spending time on hardware tuning is not an option most of the time. For the cloud vendors, the knowledge will be available and tuning for EPYC will be a one-time investment. Microsoft is already deploying AMD's EPYC in their Azure Cloud Datacenters.
Looking Towards the Future
Looking towards the future, Intel has the better topology to add more cores in future CPU generations. However AMD's newest core is a formidable opponent. Scalar floating point operations are clearly faster on the AMD core, and integer performance is – at the same clock – on par with Intel's best. The dual CCX layout and quad die setup leave quite a bit of performance on the table, so it will be interesting how much AMD has learned from this when they launch the 7 nm "Rome" successor. Their SKU line-up is still very limited.
All in all, it must be said that AMD executed very well and delivered a new server CPU that can offer competitive performance for a lower price point in some key markets. Server customers with non-scalar sparse matrix HPC and Big Data applications should especially take notice.
As for Intel, the company has delivered a very attractive and well scaling product. But some of the technological advances in Skylake-SP are overshadowed by the heavy price tags and somewhat "over the top" market segmentation.
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JohanAnandtech - Friday, July 21, 2017 - link
Thanks! It is was a challenge, and we will update this article later on, when better kernel support is available.serendip - Tuesday, July 11, 2017 - link
What idiot marketroid thought it was cool to have a huge list of SKUs and gimped "precious metals" branding? I'd like to see Epyc kicking Xeon butt simply because AMD has much more sensible product lists and there's not much gimping going on.ParanoidFactoid - Tuesday, July 11, 2017 - link
Reading through this, the takeaway seems thus. Epyc has latency concerns in communicating between CCX blocks, though this is true of all NUMA systems. If your application is latency sensitive, you either want a kernel that can dynamically migrate threads to keep them close to their memory channel - with an exposed API so applications can request migration. (Linux could easily do this, good luck convincing MS). OR, you take the hit. OR, you buy a monolithic die Intel solution for much more capital outlay. Further, the takeaway on Intel is, they have the better technology. But their market segmentation strategy is so confusing, and so limiting, it's near impossible to determine best cost/performance for your application. So you wind up spending more than expected anyway. AMD is much more open and clear about what they can and can't do. Intel expects to make their money by obfuscating as part of their marketing strategy. Finally, Intel can go 8 socket, so if you need that - say, high core low latency securities trading - they're the only game in town. Sun, Silicon Graphics, and IBM have all ceded that market.msroadkill612 - Wednesday, July 12, 2017 - link
"it's near impossible to determine best cost/performance for your application. So you wind up spending more than expected anyway. AMD is much more open and clear about what they can and can't do. Intel expects to make their money by obfuscating as part of their marketing strategy.Finally, Intel can go 8 socket, so if you need that - say, high core low latency securities trading - they're the only game in town. Sun, Silicon Graphics, and IBM have all ceded that market."
& given time is money, & intelwastes customers time, then intel is expensive.
Those guys will go intel anyway, but just sayin, there is already talk of a 48 core zen cpu, making 98 cores on a mere 2p mobo.
As i have posted b4, if wall street starts liking gpu compute for prompter answers, amdS monster apuS will be unanswerable.
nils_ - Wednesday, July 19, 2017 - link
98 cores on a 2p mobo isn't quite right if you keep in mind that the 32 core versions already constitute a 4 CPU system, unless AMD somehow manages to get more cores on a single die.nils_ - Wednesday, July 19, 2017 - link
Good analysis, although Sun and IBM are still coming out with new CPUs and at least with IBM there is renewed interest in the POWER ecosystem.eek2121 - Wednesday, July 12, 2017 - link
, but rather AMD's spanking new EPYC server CPU. Both CPUs are without a doubt very different: micro architecture, ISA extentions, <snip>Should be extensions.
intelemployee2012 - Wednesday, July 12, 2017 - link
After looking at the number of people who really do not fully understand the entire architecture and workloads and thinking that AMD Naples is superior because it has more cores, pci lanes etc is surprising.AMD made a 32 core server by gluing four 8core desktop dies whereas Intel has a single die balanced datacenter specific architecture which offers more perf if you make the entire Rack comparison. It's not the no of cores its the entire Rack which matters.
Intel cores are superior than AMD so a 28 core xeon is equal to ~40 cores if you compare again Ryzen core so this whole 28core vs 32core is a marketing trick. Everyone thinks Intel is expensive but if you go by performance per dollar Intel has a cheaper option at every price point to match Naples without compromising perf/dollar.
To be honest with so many Fabs, don't you think Intel is capable of gluing desktop dies to create a 32core,64core or evn 128core server (if it wants to) if thats the implementation style it needs to adopt like AMD?
The problem these days is layman looks at just numbers but that's not how you compare.
sharath.naik - Wednesday, July 12, 2017 - link
Agree, Most who look at these numbers will walk away thinking AMD is doing well with EPYC. The article points out the approach to testing and also states the performance challenges with EPYC, which can be missed who reading this review without the prior review on the older Xeons. For example the Big data test, I bet the newbies will walk away thinking EPYC beats the older XEONS E5 v4, as thats what the graphs show,without ever looking back at the numbers for a single 22 core Xeon e5 v4. So yes, a few back links in the article will be helpful.warreo - Wednesday, July 12, 2017 - link
Not a fanboi of either company, but care to elaborate more? I checked the original Xeon E5 v4 review. It shows that a single Xeon E5 v4 performs about 10% slower than a dual setup. Extrapolating that here, that means the single Xeon E5 v4 setup would be right around 4.5 jobs per day, which would make it roughly 50% slower than the dual Epyc and Xeon 8176.Sure, you could argue perf/dollar is better against a dual Epyc setup...but one could make the same argument against Intel's Skylake Xeons? I also wouldn't expect the performance to scale linearly anyway. Please let me know what I'm missing.