Editing XAVC-S 4K with an RX480.. am I doing it right?

Hey there Blackmagic forum,
My previous gpu, a GTX 660 got fried a month ago and after doing some research decided to pull the trigger on an RX480, 8 gigs edition. Based on the reviews it seems to be quite a capable little card, etc.
Now I installed it, set project settings in Resolve to OpenCL and quite disappointingly it performs pretty much the same as my previous card. the playback is kinda botchy and my CPU is performing at 98% (AMD FC-8350 8core / I have 24gigs ram).
This is far from the 4K promised land of uninterrupted editing...
Am I doing everything right / was this performance to be expected due to XAVCS?

All your input is greatly appreciated, thanks!

Some additional info:
I reseted my Resolve settings (I am running 12.5.4.19) which has sped things up a bit (I have been messing with rescaling options a month back). Right now it only lags when a 4K sequence starts (for 3-4 secs), then it caches up to speed.
Running two 4K XAVCS videos at the same time with overlay is pretty much impossible though.

have you tried transcoding to something else? I may be wrong but I think DR would be decoding XACV-S on the fly , and 2 streams of 4k plus decoding is a lot of info to deal with.

I have the rx470 8 Gig, 4k Prores or DNxHR is no problem.

what disc are you running from? spinning platters or SSD? GPU is only part of the equation, so the system as a whole needs to be looked at.

have you tried transcoding to something else? I may be wrong but I think DR would be decoding XACV-S on the fly , and 2 streams of 4k plus decoding is a lot of info to deal with.

I have the rx470 8 Gig, 4k Prores or DNxHR is no problem.

what disc are you running from? spinning platters or SSD? GPU is only part of the equation, so the system as a whole needs to be looked at.

Hey Jeff, indeed it seems for my more complex editing needs I will need to transcode the stuff to 1080p or so, that is something I can live with, only something new in my workflow.
And indeed, my disk setup could also be of a blame here, it is running on a dedicated harddrive, just a 7200, not an ssd or anything. To really figure out the ntire disk setup is something I am about to do.
Thanks for the info!
Btw, once on the subject, does any of you have a recommended media transcoding workflow for windows?
I found ffmpeg to be of my liking - a bit hacky though - I wonder if there are better options out there.

If your CPU is at 98% then you found a problem. It's just not fast enough for XAVC sources. Transcode/cache to DNxHR .

Get Convert 4 from hdcinematics.com for conversion.

And, no, you don't need to downscale to 1080p, it's just about transcoding from a very computational expensive codec to a lighter one. Grading in 4K should be handled just fine by your GPU, it's just that XAVC-S in 4K is very demanding on the CPU. But the lighter codecs need more bandwidth, so may need a faster drive setup.

If your CPU is at 98% then you found a problem. It's just not fast enough for XAVC sources. Transcode/cache to DNxHR .

Get Convert 4 from hdcinematics.com for conversion.

And, no, you don't need to downscale to 1080p, it's just about transcoding from a very computational expensive codec to a lighter one. Grading in 4K should be handled just fine by your GPU, it's just that XAVC-S in 4K is very demanding on the CPU. But the lighter codecs need more bandwidth, so may need a faster drive setup.

Thanks, I will look into it!