Chrome using too much CPU for video decoding/render - Mac mini 2012 + RX 460 + C...
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Chrome using too much CPU for video decoding/render - Mac mini 2012 + RX 460 + Catalina 10.15.4  


New Member
Joined: 1 year ago

Hi folks.

I have 2012 Mac mini + Radeon RX 460 2GB hooked in ATTO Thunderbolt enclosure enabled using Purge-Wrangler script ...for more details about the build click on link in my signature.

I started to encounter a problem that Chrome uses CPU almost exclusively for video decoding / rendering.
I notioced that in chrome://gpu there is something like:

"Hardware Protected Video Decode: Unavailable"

and also

Problems Detected

here's full output of that page:

CPU temps rise to 90+C and sometimes get to 100C while playing 1080p60 video (Arctic MX-2 applied 11/2019)... 
I think it might have started after that second update of macOS 10.15.4 as before that the temps went to mid 70s at max. I've had my fan set to 3000rpm constantly.

I don't remember what exactly did chrome://gpu show before the update ... I just had hardware acceleration turned on and didn't care.

Every application installed is set to prefer eGPU using the script I found on the forums. I've also checked that manually for Chrome.

But in Activity monitor only a very slight use of GPU is shown when playing video on YT... and the Chrome process for video rendering covers almost 100% of current CPU usage.
In Intel Power Gadget I can see that HD 4000 graphics is idling at 350Mhz... so that one is not being used. 

I also tried to play h265 4K movie in VLC ... the result was that it used the GPU ... but also CPU ... and it was quite choppy with a lot of lost frames.

I tried to do some research but haven't found anything helpful yet.

Could anybody help me with this problem? ... I started using eGPU especially to give the CPU more "freedom" regarding graphics tasks... but now it seems like the eGPU ain't helping much.

This topic was modified 12 months ago
2012 Mac Mini [3rd,4C,Q] + RX 460 @ 10Gbps-TB1 (Atto Thunderlink) + macOS 10.15.4 [build link]  

Reputable Member
Joined: 3 years ago


I'm not an expert with video encoding but here's what I think is going on. Neither the iGPU (HD 4000) or eGPU (RX460) have hardware acceleration for VP9 video encoding which is what many websites like youtube use. H265 aka HEVC should be hardware accelerated on the egpu, though I think I've seen some threads on here claiming problems in macos. H264 should be accelerated by either. See these tables:

I would try a chrome extension like h264ify and see if that helps. A newer AMD navi gpu (RX 5500 XT, etc.) should also come with VP9 decoding.

Mid-2012 13" Macbook Pro (MacBookPro9,2) TB1 -> RX 460/560 (AKiTiO Node/Thunder2)
+ macOS 10.15+Win10 + Linux Mint 19.1

2012 13" MacBook Pro [3rd,2C,M] + RX 460 @ 10Gbps-TB1 (AKiTiO Thunder2) + macOS 10.14.4 [build link]  

Trusted Member
Joined: 2 years ago


Did you look at Mr.Bombastics' build?

Hope your first suggestion with the chrome extension helps.

I could imagine it is not that easy to execute your second suggestion with the RX 5500 XT graphics card.

The limitations for a more powerful graphics card seems to be the ATTO Thunder Link FC 1082 and the Akyga Power Supply.

Anyway, I like this "puristic" build.



Now:    2018 Mac Mini (8th,6C,B) + RX 570 @ 32Gbps-TB3 (PowerColor Mini Pro) + macOS 10.15.4 & Win10 1909
Before: 2014 Mac Mini (4th,2C,U) + GTX 1050 Ti @ 16Gbps-TB2>TB3 (AKiTiO Node Lite) + Win10

2014 Mac Mini [4th,2C,U] + GTX 1050 Ti @ 16Gbps-TB2>TB3 (PowerColor Mini Pro) + Win10 1803 [build link]