
What DirectX 12 means for gamers and developers - JSnake
http://www.pcgamer.com/what-directx-12-means-for-gamers-and-developers/
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vardump
As a software dev who has used and benefited from AVX2, I think the last data
point in the chart is quite a bit off. Perhaps their benchmarking software
didn't support AVX2 yet (Haswell/Broadwell) yet?

> Blue depicts parallel performance, while purely sequential performance is
> shown in orange.

Sequential trend seems to totally disregard up to doubled integer vector
performance in AVX2, first introduced in Haswell. Original AVX didn't support
256-bit wide integer vectors. Also Haswell up to "doubled" [1] FLOP/cycle.

[1]: If your workload is FMA. That said, it is a pretty common FPU workload.
See for example [http://stackoverflow.com/questions/15655835/flops-per-
cycle-...](http://stackoverflow.com/questions/15655835/flops-per-cycle-for-
sandy-bridge-and-haswell-sse2-avx-avx2) for reference.

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vardump
The chart seems to indicate about 25 GFLOPS for sequential performance, while
real value is up to 100 GFLOPS theoretical at 3.1 GHz on Haswell/Broadwell on
a single core.

While realistic single core performance won't of course be approaching 100
GFLOPS, 25 is a pretty lowball value.

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wtallis
Is it possible that they're using "sequential" strictly, to mean that the
arithmetic isn't vectorized? What's the scalar throughput like?

~~~
vardump
Scalar output would be way less than that number, 25 GFLOPS. At most 2x clock
frequency. It's likely their benchmark just doesn't support AVX2 (and FMA
[1]).

You get about 25 GFLOPS if you use SSE only.

[1]:
[https://en.wikipedia.org/wiki/FMA_instruction_set](https://en.wikipedia.org/wiki/FMA_instruction_set)

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microcolonel
*What DirectX 12 means to Windows gamers and Windows developers.

The complete lack of mention of Vulkan in this article is suspect.

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tormeh
Not really. DirectX 12 has incredible mindshare among consumers and, I sadly
suspect, game developers simply due to the name.

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TwoBit
That article talks like Mantle was the first version of this kind of API. Sony
Playstation has been doing this for nearly ten years.

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rational-future
Not much. Almost all high-budget games are still developed for consoles first.
The hardware inside Xbox One doesn't support DX 12.

~~~
mwilcox
Xbox One literally runs Windows

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objclxt
It certainly doesn't _literally_ run Windows for games. The Xbox One is a
hypervisor based system where a Windows 8 based OS is used for utility
applications and user interface, but a custom OS is used for the games[1]. The
believe the latter has as much in common with Windows as the Xbox 360 OS (not
a huge amount).

[1][https://en.wikipedia.org/wiki/Xbox_One_system_software](https://en.wikipedia.org/wiki/Xbox_One_system_software)

