Clock speed and core count matter much more than ECC. I wouldn't chase ECC support for general dev machines.
On Thu, Nov 2, 2017 at 6:46 PM, Gregory Szorc <g...@mozilla.com> wrote: > On Thu, Nov 2, 2017 at 3:43 PM, Nico Grunbaum <ngrunb...@mozilla.com> wrote: > >> For rr I have an i7 desktop with a base clock of 4.0 Ghz, and for building >> I use icecc to distribute the load (or rather I will be again when bug >> 1412240[0] is closed). The i9 series has lower base clocks (2.8 Ghz, and >> 2.6Ghz for the top SKUs)[1], but high boost clocks of 4.2 Ghz. If I were >> to switch over to an i9 for everything, would I see a notable difference in >> performance in rr? >> > > Which i7? You should get better CPU efficiency with newer > microarchitectures. The i9's we're talking about are based on Skylake-X > which is based on Skylake which are the i7-6XXX models in the consumer > lines. It isn't enough to compare MHz: you need to also consider > microarchitectures, memory, and workload. > > https://arstechnica.com/gadgets/2017/09/intel-core-i9-7960x-review/2/ has > some single-threaded benchmarks. The i7-7700K (Kaby Lake) seems to "win" > for single-threaded performance. But the i9's aren't far behind. Not far > enough behind to cancel out the benefits of the extra cores IMO. > > This is because the i9's are pretty aggressive about using turbo. More > aggressive than the Xeons. As long as cooling can keep up, the top-end GHz > is great and you aren't sacrificing that much perf to have more cores on > die. You can counter by arguing that the consumer-grade i7's can yield more > speedups via overclocking. But for enterprise uses, having this all built > into the chip so it "just works" without voiding warranty is a nice trait :) > > FWIW, the choice to go with Xeons always bothered me because we had to make > an explicit clock vs core trade-off. Building Firefox requires both many > cores for compiling and fast cores for linking. Since the i9's turbo so > well, we get the best of both worlds. And at a much lower price. Aside from > the loss of ECC, it is a pretty easy decision to switch. > > >> -Nico >> >> [0] https://bugzilla.mozilla.org/show_bug.cgi?id=1412240 Build failure in >> libavutil (missing atomic definitions), when building with clang and icecc >> >> [1] https://ark.intel.com/products/series/123588/Intel-Core-X- >> series-Processors >> >> On 10/27/17 7:50 PM, Robert O'Callahan wrote: >> >>> BTW can someone forward this entire thread to their friends at AMD so AMD >>> will fix their CPUs to run rr? They're tantalizingly close :-/. >>> >>> Rob >>> >> >> _______________________________________________ >> dev-platform mailing list >> dev-platform@lists.mozilla.org >> https://lists.mozilla.org/listinfo/dev-platform >> > _______________________________________________ > dev-platform mailing list > dev-platform@lists.mozilla.org > https://lists.mozilla.org/listinfo/dev-platform _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
