[Situation improved] PSA: S905X cpu is significantly slower than S905 cpu

**mmpp** · March 1, 2017 at 10:03 AM

Hello,

in the datasheets and comparisons from amlogic and third-party websites, the SoCs 905 and 905X look very similar: They both have a "Quad core Cortex A53 @ 2.0 GHz" (or 1.5 GHz, if the sheet was fixed after the shady frequency scaling of the amlogic kernel came to light) and a "Penta-core ARM Mali-450MP" GPU. The main difference that is noted are the different video codecs that are supported by the hardware: S905X adds VP9 and HEVC Main10 with HDR decoding and the neccessary HDMI 2.0b link.

Last week I received a S905X box and did some comparisons. While both worked fine with libreelec, and hardware decoded video was the same; software decoded video showed significant differences: S905 would play 720p h.264 10-bit ("hi10p") encoded videos just fine, while S905X would not be watchable at all: video was jerky, with many dropped frames and severe a/v sync issues.

The reason appears to be a difference in the cpu cores: During playback, the S905 was at less than 80% load per core, while the S905X was at 100% load. Further searches found that benchmarks under android also show a difference between S905 and S905X. See Amlogic S905 vs S905X Benchmarks Comparison

Conclusion: If you are interested in cpu-bound applications on your device, like software decoded video, emulation and games, pick the S905 over the S905X.
[hr]

Update 2017/03/17: With version 8.0.0f the S905X can keep up with 720p h264 10bit software decoding.

**koenkooi** · March 1, 2017 at 10:28 AM

Did you test in 64bit more, 32bit more or both?

**mmpp** · March 1, 2017 at 10:47 AM

Kernel is always 64 bit. I compared in 32 bit userland.

In earlier tests, S905 64 bit userland compared to 32 bit userland was no change for software decoder cpu load.

kostaman · March 1, 2017 at 11:00 AM

Quote from mmpp

Conclusion: If you are interested in cpu-bound applications on your device, like software decoded video, emulation and games, pick the S905 over the S905X.

Thanks.
I only purchased one s905x and am a little more critical than you.
I will not purchase one of these again.
"4K VP9 hardware decoding"? I couldn't be less interested.

Pelican · March 1, 2017 at 11:32 AM

"hardware decoded video was the same"
My experience is just different.
My S905X based M8S II much better then my S905 Mini MX-G regarding of playing high bitrate videos.
I run only LE on both device. Never tried software decoded videos or playing games, just watching movies from 20-40 GB mkv or BD and showing my pictures to my friends..
Also I have a collection of 4k VP9 videos which only playable on S905X only.
The only disadvantage for me is the lack of gigabit lan on S905X boxes.

**mmpp** · March 1, 2017 at 11:37 AM

Interesting, I had absolutely no difference in hardware decoded playback. I tried several files I made with makemkv from my BD collection.

What kind of problems did you have with high bitrate videos on S905?

Pelican · March 1, 2017 at 2:32 PM

Quote from mmpp

Interesting, I had absolutely no difference in hardware decoded playback. I tried several files I made with makemkv from my BD collection.

What kind of problems did you have with high bitrate videos on S905?

Try jellyfish test videos and you will see the difference.

**mmpp** · March 1, 2017 at 2:45 PM

Those work until the network interface becomes the bottleneck.

Ftelf · March 1, 2017 at 2:47 PM

mmpp What was the sustained temperature of the cpu during the evaluation ? Quality of the CPU cooler on those box vary a lot. One had a tiny 10x10x5mm one, which would barely cool a memory chip, the other 25x25x10mm. Once the cpu temp went up, it is a one-way (throttling-lagging-100%-cpu-usage).

Pelican · March 1, 2017 at 2:57 PM

Quote from mmpp

Those work until the network interface becomes the bottleneck.

My S905 box had gigabit lan so that was not the bottleneck for sure.
Try them from a USB drive to see the higher ones.

**mmpp** · March 1, 2017 at 3:11 PM

Quote from Ftelf

mmpp What was the sustained temperature of the cpu during the evaluation ? Quality of the CPU cooler on those box vary a lot. One had a tiny 10x10x5mm one, which would barely cool a memory chip, the other 25x25x10mm. Once the cpu temp went up, it is a one-way (throttling-lagging-100%-cpu-usage).

To limit the effect of overheating, I compared the playback immediately after I started both boxes. From the first second, the S905x cannot keep up decoding the files and CPU is at 100%.

Ftelf · March 1, 2017 at 7:38 PM

OK, seems like s905x is really a bit slower. Amlogic S905 vs S905X Benchmarks Comparison
The differences are questioned here in the discussion, but together it makes sense.

Frisk · March 1, 2017 at 9:22 PM

Is it possible to overcloak these chips?

It seems possible for the mali gpu.

**kszaq** · March 2, 2017 at 7:15 AM

So far the only S905 device that you can overclock is Odroid-C2 and this is possible only because Hardkernel developers worked hard on tuning bootloader and kernel.

From some benchmarks I did when testing libdvbcsa speed I can say that S905X is indeed a little bit slower than S905 - less than 10% slower.

About Mali GPU speed there was a bug in device trees provided that limited Mali clock to 666MHz for S905. Now with the latest device trees that I provide in my builds (and soon in official LE) you are able to run Mali at 792MHz for S905 and 744MHz for S905X.

About decoding pipeline the only significant difference in code is for 4K H.264 videos but I cannot comment on which one is better.

**mmpp** · March 2, 2017 at 7:19 AM

CPU and DRAM clock speeds are setup by the early-stage boot process. There is some information on the odroid forum (where they found out about the fake frequency settings in the kernel) but I have no idea if or how one can replace the mentioned files on generic tv boxes.

You can read about the odroid c2 "over"clocking here: ODROID Forum • View topic - No performance difference between 1.5, 1.75 & 2GHz

**mmpp** · March 17, 2017 at 10:31 AM

I usually do not crosspost but as some might find this thread by search, I want to note the current development here as well:

Quote from kszaq

It's been a quiet week for LE 8.0 and Kodi 17 so let's break something.

8.0.0f posted in OP with an experimental change to HW decoder that might improve seek and channel switching times - please report if they're better, worse or the same. There is also a performance bump for S905X (it's still a bit slower than S905 but the gap is now much smaller) and improvement to Bluetooth audio. Enjoy!

I can confirm that software decoded playback of 720p h264 10bit videos, which was dropping a lot of frames on S905X and worked fine on S905 on earlier versions has improved on S905X. I only tried a few files and currently cannot do side-by-side comparisons, but the tested files were watchable. Big thumbs up to kszaq for this "bump".

**mmpp** · June 7, 2017 at 10:45 PM

I am very happy to update this old thread: with the latest "full nougat" kernel developments by kszaq and johngalt, the gap between S905x and S905 performance has been reduced even further.

My S905x box can now flawlessly software decode several cpu-intensive 720p hi10p files from my collection that I had earmarked when I did the comparison earlier this year.

frequenzy · June 10, 2017 at 4:57 PM

Quote from mmpp

I am very happy to update this old thread: with the latest "full nougat" kernel developments by kszaq and johngalt, the gap between S905x and S905 performance has been reduced even further.

My S905x box can now flawlessly software decode several cpu-intensive 720p hi10p files from my collection that I had earmarked when I did the comparison earlier this year.

what is the build that you installed?