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 Turbo Modes
A last minute detail from Intel yesterday was information on the Turbo modes. As expected, not all of the processors actually run at their rated/base frequency: most will apply a series of turbo modes depending on how many cores are registered as ‘active’. Each core can have its frequency adjusted independently, allowing VMs to take advantage of different workload types and not be hamstrung by occupants on other VMs in the same socket. This becomes important when AVX, AVX2 and AVX-512 are being used at the same time.
Most of the turbo modes are a sliding scale, with the peak turbo used when only one or two cores are active, sliding down to a minimum frequency that may be the ‘base’ frequency or just above it. There’s a lot of information for the parts here, so we’ll break it down into stages.
First up, a look at the Platinum 8180 in the different modes:
It should be worth noting what the base frequency actually is, and some of the nuance in Intel’s wording here. The base frequency is the guaranteed frequency of the chip – Intel sells the chip with the base frequencies as the guarantee, such that when the chip is not idle and not in normal conditions (i.e. when not in thermal power states to reduce temperature) should operate at this frequency or above it. Intel also lists the per-core turbo frequencies as ‘Maximum Core Frequencies’ indicating that the processors could be running lower than listed, depending on power distribution and requirements in other areas of the chip (such as the uncore, or memory controller). It’s a vague set of terms but ultimately the frequency is determined on the fly and can be affected by many factors, but Intel guarantees a certain amount and provides guides as to what it expects the turbo frequencies to be.
As for the Platinum 8180, it keeps its top turbo modes while up to two cores are active, and then drops down. It does this again for another two cores, and a further two cores. From this point, under non-AVX load the CPU is pretty much the same frequency until >20 cores are loaded, but does not decrease that much in all. For AVX 2.0 and AVX-512, the downward slope of more cores means less frequency continues, with AVX-512 taking a bigger jump down at 13 cores loaded. The final turbo frequency for AVX-512 running on all cores is 2.3 GHz.
Comparing the two 28-core CPUs for which we have turbo information gives this graph. The numbers relate to the number of cores need to be loaded for that frequency.
Both processors are equal to each other for dual core loading, but the separation occurs when more cores are loaded. As we move through to AVX 2.0 and AVX-512, it is clear where the separations are in performance – to get the best for variable core loading, the more expensive processors are required.
Here’s the big table for all the processors on Non-AVX loading:
Despite the 2.0/2.1 GHz base on most of the Platinum series, all the CPUs will turbo up to 3.7-3.8 GHz on low core loading except for the lower power Platinum 8153. For users wanting to strike a good balance between the core count and frequency, the Gold 6154 is probably the place to be: 18 cores that will only ever run at 3.7 GHz with non-AVX loading (3.5-2.7 GHz on AVX-512 depending on core count), and will be $3543 as a list price at 205W. It is perhaps worth noting that this will likely top any of the Core i9 processors planned: at 18-cores and 205W for 3.7 GHz, the Core i9-7980XE which will have 18 cores but run 165W will likely be clocked lower (but also only ~$2000).
Moving onto AVX2.0 and AVX-512:
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deltaFx2 - Thursday, July 13, 2017 - link
"Can you mention one innovation from AMD that changed the world?" : None. But the same applies to Intel too, save, I suppose, the founders (Moore and Noyce) contributions to IC design back when they were at Fairchild/Shockley. That's not Intel's contribution. Computer Architecture/HPC? That's IBM. They invented the field along with others like CDC. Intel is an innovator in process technology, specifically manufacturing. Or used to be... others are catching up. That 3-yr lead that INtel loves to talk about is all but gone. So with that out of the way...AMD's contributions to x86 technology: x86-64, hypertransport, integrated memory controller, multicore, just to name a few. Intel copied all of them after being absolutely hammered by Opteron. Nehalem system architecture was a copy-paste of Opteron. It is to AMD's discredit that they ceded so much ground on the CPU microarchitecture since then with badly executed Bulldozer, but it was AMD that brought high-performance features to x86 server. Intel would've just loved to keep x86 on client and Itanium on server (remember that innovative atrocity?). Then there's a bunch on the GPU side (which INtel can't get right for love or money), but that came from an acquisition, so I won't count those.
"AMD exists because they are always inferior". Remember K8? It absolutely hammered intel until 2007. Remember Intel's shenanigans bribing the likes of Dell to not carry K8? Getting fined in the EU for antitrust behaviors and settling with AMD in 2010? Not much of a memory card on you, is there?
AMD gaining even 5-10% means two things for intel: Lower margins on all but the top end (Platinum) and a loss in market share. That's plain bad for the stock.
"Intel is a data center giant have head start have the resources...". Yes, they are giants in datacenter compute. 99% market share. Only way to go from there is down. Also, those acquisitions you're talking about? Only altera applies to the datacenter. Also, remember McAfee for an eye-watering $7.8 bn? How's that working out for them?
Shankar1962 - Wednesday, July 12, 2017 - link
Nvidia who have been ahead than Intel in AI should be the more competent threatHow much market share Intel loses depends on how they compete against Nvidia
Amd will probably gain 5% by selling products for cheap prices
Intel controls 98/99% share so it's inevitable to lose a few % as more players see the money potential but unless Intel loses to Nvidia there is annuphill battle for Qualcomm ARM.
HanSolo71 - Wednesday, July 12, 2017 - link
Could you guys create a Benchmark for Virtual Desktop Solutions? These AMD chips sound awesome for something like my Horizon View environment where I have hundreds of 2 core 4GB machines.Threska - Saturday, July 22, 2017 - link
For VDI wouldn't either an APU setup, or CPU+GPU be better?msroadkill612 - Wednesday, July 12, 2017 - link
Kudos to the authors. I imagine its gratifying to have stirred such healthy & voluminous debate :)milkod2001 - Thursday, July 13, 2017 - link
Are you guys still updating BENCH results? I cannot find there benchmark results for RYZEN CPUs when i want to compare them to others.Ian Cutress - Friday, July 14, 2017 - link
They've been there since the launchAMD (Zen) Ryzen 7 1800X:
http://www.anandtech.com/bench/product/1853
KKolev - Thursday, July 13, 2017 - link
I wonder if AMD'd EPYC CPU's can be overclocked. If so, the AMD EPYC 7351P would be very interesting indeed.uklio - Thursday, July 13, 2017 - link
How could you not do Cinebench results?! we need an answer!JohanAnandtech - Thursday, July 13, 2017 - link
I only do server benchmarks, Ian does workstation. Ian helped with the introduction, he will later conduct the workstation benchmarks.