Hacker News Reader

Comment by old-gregg | Hacker News Reader

Does anyone have a theory for why Ryzens are beaten so badly by Intel in the Chromium compile benchmark?

I think on GCC or Clang Threadripper should be much better (see link on my other reply)

And also Arstechnica reported much better numbers, I think Anantech either had a bad config or there is a bug in the compiler they used.

https://arstechnica.co.uk/gadgets/2017/08/amd-threadripper-r...

The arstechnica numbers surprise me, given the sheer difference between the Ryzen 7 1800X and the Threadripper 1920X compared with the 1920X and the 1950X; either you've reached more or less peak parallelism by 16 cores, or the larger L3 cache and quad-channel memory makes the difference. Or something's changed in the benchmark setup (be it the compiler or whatever) since the 1800X was done.

On Twitter, the reviewer blamed it on Ryzen's L3 cache being a victim cache [1] (which I don't really understand; maybe it's related to having ephemeral data structures displace long-lived ones?). I think it's also been stated elsewhere that the Intel chips dominate during linking, which is a large chunk of the overall build time for Chromium.

[1] https://twitter.com/IanCutress/status/868799386079420416

Cross-core communication

Actually its a problem with Visual studio, Ryzen utterly destroys comptetition when it comes to compilation. Unfortunately Anandtech does not test with GCC or Clang.

http://www.phoronix.com/scan.php?page=article&item=ryzen-kab...

Reply on news.ycombinator.com