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
Intel's Optimized Turbo Profiles
Also new to Skylake-SP, Intel has also further enhanced turbo boosting.
There are also some security and virtualization enhancements (MBE, PPK, MPX) , but these are beyond the scope this article as we don't test them.
Summing It All Up: How Skylake-SP and Zen Compare
The table below shows you the differences in a nutshell.
| AMD EPYC 7000 |
Intel Skylake-SP | Intel Broadwell-EP |
|
| Package & Dies | Four dies in one MCM | Monolithic | Monolithic |
| Die size | 4x 195 mm² | 677 mm² | 456 mm² |
| On-Chip Topology | Infinity Fabric (1-Hop Max) |
Mesh | Dual Ring |
| Socket configuration | 1-2S | 1-8S ("Platinum") | 1-2S |
| Interconnect (Max.) Bandwidth (*)(Max.) |
4x16 (64) PCIe lanes 4x 37.9 GB/s |
3x UPI 20 lanes 3x 41.6 GB/s |
2x QPI 20 lanes 2x 38.4 GB/s |
| TDP | 120-180W | 70-205W | 55-145W |
| 8-32 | 4-28 | 4-22 | |
| LLC (max.) | 64MB (8x8 MB) | 38.5 MB | 55 MB |
| Max. Memory | 2 TB | 1.5 TB | 1.5 TB |
| Memory subsystem Fastest sup. DRAM |
8 channels DDR4-2666 |
6 channels DDR4-2666 |
4 channels DDR4-2400 |
| PCIe Per CPU in a 2P |
64 PCIe (available) | 48 PCIe 3.0 | 40 PCIe 3.0 |
(*) total bandwidth (bidirectional)
At a high level, I would argue that Intel has the most advanced multi-core topology, as they're capable of integrating up to 28 cores in a mesh. The mesh topology will allow Intel to add more cores in future generations while scaling consistently in most applications. The last level cache has a decent latency and can accommodate applications with a massive memory footprint. The latency difference between accessing a local L3-cache chunk and one further away is negligible on average, allowing the L3-cache to be a central storage for fast data synchronization between the L2-caches. However, the highest performing Xeons are huge, and thus expensive to manufacture.
AMD's MCM approach is much cheaper to manufacture. Peak memory bandwidth and capacity is quite a bit higher with 4 dies and 2 memory channels per die. However, there is no central last level cache that can perform low latency data coordination between the L2-caches of the different cores (except inside one CCX). The eight 8 MB L3-caches acts like - relatively low latency - spill over caches for the 32 L2-caches on one chip.
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CajunArson - Tuesday, July 11, 2017 - link
Would a high-end server that was built in 2014 necessarily update? Maybe not.Should a high-end server with a brand new microarchitecture use the most recent version of the software if it has any expectation of seeing a real benefit? Absolutely.
If this was a GPU review and Anandtech used 2 year old drivers on a new GPU (assuming they even worked at all) we wouldn't even be having this conversation.
BrokenCrayons - Tuesday, July 11, 2017 - link
Home users playing video games are in a different environment than you find in a business datacenter. There's a lot less money to be lost when a driver update causes a performance regression or eliminates a feature. Conversely, needlessly updating software in the aforementioned datacenter can result in the loss of many millions if something goes wrong.wallysb01 - Tuesday, July 11, 2017 - link
Conversely, having stuff working, but unnecessarily slowly costs money as well. Its a balance, and if you're spending hundreds of thousands or even millions on a cluster/data center/what have you, you'd probably want to spend at least a little bit of time optimizing it, right?Icehawk - Tuesday, July 11, 2017 - link
Most of the businesses I have worked for, ranging from 10 people to 50k, use severely outdated software and the barest minimum of patching. Optimization? HA!For example I work for a manufacturer & retailer currently, our POS system was last patched in 2012 by the vendor and has been replaced by at least two versions newer. We have XP machines in each of our stores as that is the only OS that can run the software.
The above is very typical. The 50k company I worked for had software so old and deeply entrenched that modernizing it is virtually impossible. My current company is working on getting to a new product... that was new in 2012 and has also been replaced with a newer version. Whee!
Icehawk - Tuesday, July 11, 2017 - link
One other thing - maybe the big shops actually do test/size but none of the places I have worked at and have been involved in do any testing, benchmarking, etc. They just buy whatever their preferred vendor gives them that meets the budget and they *think* will work. My coworker is in charge (lol) of selecting servers for a new office... he has no clue what anything in this article is. He has never read a single review, overview, or test of a processor. I could keep going on like this :(0ldman79 - Wednesday, July 12, 2017 - link
Icehawk's comments are so accurate it is scary.I can't tell you how many businesses running custom *nix software running in a VM on a Windows server.
They're not all about speed. Reliability is the single most important factor, speed is somewhere down the line. The people that make those decisions and the people that drink coffee while they're waiting on the machines are very different.
Neither understand that it could all be done so much better and almost all of them are utterly terrified at the concept of speeding up the process if it means *any* changes are made.
JohanAnandtech - Friday, July 21, 2017 - link
We did test with NAMD 2.12 (Dec 2016).sutamatamasu - Tuesday, July 11, 2017 - link
Glad, AMD make back again to this segment, now we can only see what can Raja to do for server market with Radeon instinct.Kaotika - Tuesday, July 11, 2017 - link
So this confirms that the previous information regarding Skylake-X core configurations was wrong, and 12-core variant is in fact using HCC-core instead of LCC-core?Ian Cutress - Tuesday, July 11, 2017 - link
We corrected that in our Skylake-X review.