Unexpected benefit with Ryzen – reducing power for build server

Not every workload is memory bandwidth bound like his &quot;make -j16&quot; compile. Some workloads need memory latency or fast inter-core (and inter-socket) operations (e.g. RDBMS OLTP), some need CPU throughput (e.g. HPC), some need best possible single thread CPU performance (e.g. some gaming).<p>As he wrote, CPUs are most efficient (compute per Watt) at a specific frequency, and if his CPU mostly waits for RAM, this can be done at low power.<p>It&#x27;s probably possible to create x86-64 CPUs with narrower backends (fewer execution units) with microcode-emulated 128 and 256 bit registers&#x2F;operations (and maybe even emulated FPU) and get a cheaper and faster build server, if it was economical to fab such narrow-use-case chips (those would be good for redis&#x2F;memcached too I imagine).

This is to be expected. Since 180Watt is not the default TDP of Ryzen 2700X, the default TDP is 105Watt. <a href="https:&#x2F;&#x2F;www.amd.com&#x2F;en&#x2F;products&#x2F;cpu&#x2F;amd-ryzen-7-2700x" rel="nofollow">https:&#x2F;&#x2F;www.amd.com&#x2F;en&#x2F;products&#x2F;cpu&#x2F;amd-ryzen-7-2700x</a><p>Which mean the CPU is already shipped with the reasonable performance&#x2F;watt TDP and over-TDP it will give diminish return in performance gain.<p>However, It would be interesting to see benchmark in much lower TDP than 105Watt and see how far the TDP can go down before big drop in performance.

Calling this &quot;Unexpected&quot; seems like a bit of a stretch. In particular this part:<p>&gt; Of course, in the server space, we&#x27;ve known for a long time that maximum efficiency occurs with a high number of cores running at lower frequencies, and that efficiency trumps performance on machines with high core counts. But I never considered that the consumer Ryzen CPUs could also benefit from the same thing until now.<p>makes no sense. This principal applies to all CPUs from the smallest SoCs to the largest server CPUs, why on Earth would you <i>not</i> expect it to apply to desktop CPUs?<p>You could do the same thing with a 6 core i7 and 2133 memory. Intel CPUs have long supported an adjustable power limit to constrain operating frequency based on power consumption just like he describes for Ryzen.

180w to 85w is pretty impressive.<p>I didn&#x27;t know that compilation was memory speed limited.<p>Are there any good benchmarks on it?<p>Anyone have any examples of getting faster memory boosting build speed?<p>Over the last few years I&#x27;d settled into thinking that high speed ram barely did anything. I guess I was wrong!

I think the claim that parallel compilation with gcc is memory <i>bandwidth</i> bound is unlikely. gcc is known to be a very pointer-chasy, branch-mispredicty load that is highly sensitive to memory <i>latency</i> - far from a streaming load that is sensitive to raw bandwidth.<p>Still, the conclusion holds: if most of the time is spent waiting for values to come back from memory, a higher core frequency has strongly diminishing returns.

Short form and generalized: when one subsystem of a larger system is not your bottleneck, it&#x27;s often possible to lower the resources for that part of the system without impacting overall performance.

Any server-hosting with Ryzen + ecc-ram ?

He doesn&#x27;t seem to mention what the build times were with the Xeon.

Has anyone encountered webpack and C# compilation benchmarks that compare Ryzen and Intel?

Is this the amiga hacker&#x2F;dragonflyBSD main dev? Why nobody has handed a 2990wx to this man?