Analyzing Performance Per Dollar

While measuring the performance per watt is an interesting metric, workstation processors are at the top of the stack when it comes to power consumption: the point of these processors (typically) is getting work done fast, and their users don't mind using a bit more power to get there. When it comes to designing a workstation level system for an office, the person who signs off on the project is not going to look at the performance per watt - they are going to look at the performance per dollar. Does this purchase represent the best value for the environment, and is the purchase likely to give us the best return? The following graphs attempt to answer that information, and we've chosen a varied selection including variable threaded loads.

For this analysis, we've taken all of the processors we have tested from what Intel has launched in 2017. This covers all of the consumer level Kaby Lake-S i7 and i5 parts (except T), the high-end desktop Kaby Lake-X processors, and all the high-end Skylake-X desktop parts. This is represented in the graphs in blue under the 'Intel 2017' title. From AMD, we have all eleven AMD Ryzen processors tested, under the red line.

Compile Performance Per Dollar

One of our popular benchmarks is our compile test. This takes a fixed version of Chromium v56, and runs it through the MSVC compiler with linking as per the directions given on by the Chromium developers. A typical test can run from 40 minutes to 3 hours depending on the processor, and taxes the single thread, the multi-thread and the memory performance of the system. We've seen that it does not particularly take kindly to processors with victim caches, such as Skylake-X or AMD Ryzen, with limited scaling on the code workflow. Despite the per-core performance dip from Skylake-S to Skylake-X, the top processor still has the best absolute performance. Converting our data to the number of compiles per day per dollar gives the following graph:

The cheaper end of the graph is surprisingly high, dominated by Intel's dual-core Pentium (with hyperthreading) being offered for super low prices. In the standard 'consumer' price range below $300, the mid-range Ryzen processors have a slight advantage, but, beyond the Ryzen 7 1700, Intel has the performance per dollar advantage all the way out to $2000.

Agisoft Performance Per Dollar

The Agisoft Photoscan software has been a key part of our performance testing for several years, demonstrating a true office workflow: archival purposes of taking 2D photos and converting them into 3D models. This is a computationally interesting algorithm, involving multiple single-threaded and multi-threaded stages.

Due to the single threaded elements of the algorithm, linear scaling is not observed as we ramp up through the core counts. At the mid-range consumer processor pricing, the twelve-thread Ryzen 5 processors sit above the quad-thread Core i5 parts, but beyond $330 or so, as we move into Intel's quad-core offerings and above, the performance per dollar is solely on Intel's side.

Blender Performance Per Dollar

The Blender benchmark has been an interesting debate in the last few months, with the new architectures from Intel and AMD pushing updates into the code for faster rendering. Our test takes a well used Blender release and one of the standard benchmarks (rather than anything vendor specified). Results are given in renders of this benchmark per day per dollar.

Interestingly AMD takes the peak PPD across the full range. At $999, where the competition is expected to be highest, AMD has over a 10% advantage. In the four digit range, even though the PPD of Intel's processors is lower, the absolute performance is still better. For our Blender test, this translates so a few seconds over a 2-3 minute test.

Cinebench R15 nT Performance Per Dollar

Next we move into the pure multithreaded benchmarks, which can be a significant number of workstation workloads. Here Intel might be at a disadvantage, with AMD offering more cores and more threads at each price point - Intel's IPC advantage will have to offset this in order to move ahead.

To lay some background here: AMD has been plugging Cinebench R15 nT benchmark numbers since the launch of Zen, citing better PPD. Intel's rebuttal is that in absolute performance, when you need the absolute best results, their hardware still wins.

Corona Rendering Performance Per Dollar

Ray tracing is another example of light threads taking advantage of more cores, more frequency, higher IPC and accelerated intructions with fast FP throughput. Citing back to Johan's EPYC review again, which showed AMD's good base FP performance, it will be an interesting comparison.

Similar to some of the previous graphs, the best PPD is held at Intel's low end Pentium processors - however these do not give the best overall throughput. In the mainstream price range, the Ryzen 5 1600 and 1600X are suprising peak results. In the $500-$800 range, Intel and AMD are about equal, however at $999 the Threadripper is ahead of the Core i9. Again, at the $1500+ range, Intel offers the better overall throughput, despite the lower PPD.

Power Consumption and Power Efficiency Intel Core i9-7980XE and Core i9-7960X Conclusion
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  • Krysto - Monday, September 25, 2017 - link

    Yes, it's total bullshit that they are misinterpreting what TDP is. I imagine this is how they'll get away with claiming a lower TDP than the real one in the 8700k chip, too, which has low base clock speed, but the super-high Turbo-Boost, which probably means the REAL TDP will go through the rough when that Turbo Boost is maximized.

    This is how Intel will get to claim that its chips are still faster than AMD "at the same TDP" (wink wink, nudge nudge).
  • Demigod79 - Monday, September 25, 2017 - link

    "What a load of ignorance. Intel tdp is *average* power at *base* clocks, uses more power at all core turbo clocks here. Disable turbo if that's too much power for you."

    I find it ironic that you would call someone ignorant, then reveal your own ignorance about the TDP and turbo clocks.
  • Spunjji - Monday, September 25, 2017 - link

    It is now, it wasn't before. Wanna bet on how many people noticed?
  • SodaAnt - Monday, September 25, 2017 - link

    I'm quite curious what happens if your system cooling simply can't handle it. I suspect if you designed a cooling solution which only supported 165W the CPU would simply throttle itself, but I'm curious by how much.
  • ZeDestructor - Monday, September 25, 2017 - link

    Strictly speaking, all forms of Turbo boost are a form of vendor-sanctioned overclocking. The fact that measured power goes beyond TDP when at max all-core turbo should really not be all that surprising. The ~36% increase in power for ~31% increase in clocks is pretty reasonable and inline when you keep that in mind. Especially when you factor that there has to have been a bit of extra voltage added for stability reasons (power scales linearly with clocks and current, and quadratically to exponentially with voltage).
  • Demigod79 - Monday, September 25, 2017 - link

    I agree. Everything looked good until that page. 190 watts is unacceptable, and Intel needs to correct this right away - either make the CPU run within the TDP limit, or update the TDP to 190 watts in the specs.
  • HStewart - Monday, September 25, 2017 - link

    It funny that people complain about CPU watts but never about external GPU watts. Keep in mind the GPU is smaller amount of area.
  • artk2219 - Monday, September 25, 2017 - link

    They most certainly do, that is one of the biggest gripes against Vega 64, people do seem to have short memory on how high GPU TDP's used to be however.
  • IGTrading - Tuesday, September 26, 2017 - link

    On a video card, the same manufacturer takes responsibility for the GPU, cooling system, design, PCB, components and warranty.

    On the CPU, you have somebody else designing the cooling system, the motherboard, the power lines and they all have to offer warranty for their components while Intel is only concerned with the CPU.

    If the CPU is throttling or burnt out, they will say "sufficient cooling was not provided" and so on ...

    It is a whole lot different.
  • whatevs - Tuesday, September 26, 2017 - link

    Thermal throttling is not a burn out and not a warranty event, you don't get to warranty your gpu when it throttles under load, cooling warranty does not include cpu/gpu chip performance and
    Intel designed the ATX specification and the electrical specification for the boards.

    You clearly don't know the things you're talking about.

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