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Drivers & Software

rellith
Adept II
Adept II

Crossfire RX Vega 64 - Prim shaders - HBCC

So after a week or two playing around with RX Vega 64's it took a little bit of time to work out some of the issues as to why i couldn't get them to work in games.
Now that i have that out of the way I've noticed that if i have any of the 3 presets the cards play nice with with each other and games in turn run fantastic. However the moment i touch any overclocks the cards still run stable but i start to get frame dips and both cards fluctuate in power even if i undervolt them.

Am i missing something that has not been apparent in past CF configs? and if its possible to have HBCC on with CF or is that something that will only work with one card? I also keep hearing Prim shaders is something that is not quite running at the moment is there any truth to that and if so can i be pointed in a direction to do some reading on it?

Thank you.

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10 Replies
amdmatt
Community Manager
Community Manager

Re: Crossfire RX Vega 64 - Prim shaders - HBCC

HBCC should work with 2 GPUs in MGPU, i have reported this issue to engineering for investigation.

Prim Shaders requires dev work to implement as far as i know.

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rellith
Adept II
Adept II

Re: Crossfire RX Vega 64 - Prim shaders - HBCC

Hello,

Thanks for your reply, when you say HBCC should work in MGPU should i see the slider? I dont see it and if its meant to be there is there a work around to bring it up? HBCC has really good gains in some games with 1 card and would be cool to see those same gains in CF/MGPU

From what I read prim shaders does not require game dev integration like other culling in the past hence its name primitive shaders, it's early in the pipeline. I could have my information wrong however.

amdmatt
Community Manager
Community Manager

Re: Crossfire RX Vega 64 - Prim shaders - HBCC

Yes the slider should be there, so it is likely a bug.

rellith
Adept II
Adept II

Re: Crossfire RX Vega 64 - Prim shaders - HBCC

HBCC confirmed to be or should be working with CF/MGPU? I just can't find information to say it is.

nemesis_ie
Adept II
Adept II

Re: Crossfire RX Vega 64 - Prim shaders - HBCC

Any update on this @AmdMatt?

As of Adrenalin, the HBCC slider is still not showing and for mining workloads, when CF is enabled it is much slower, this hints at HBCC not being on in CF.

Also, is the compute/game switch supposed to be visible for Vega? I've never seen this option appear in any Vega driver to date (I have had V64s since launch).

Thanks!

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amdmatt
Community Manager
Community Manager

Re: Crossfire RX Vega 64 - Prim shaders - HBCC

HBCC is only compatible with Windows 10 64bit. HBCC is not compatible with CrossFire. If you disable CrossFire and restart your system, each GPU should have its own tab within Radeon Settings and a HBCC Segment toggle.

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nemesis_ie
Adept II
Adept II

Re: Crossfire RX Vega 64 - Prim shaders - HBCC

Thanks for the clarification, I really just wanted this made clear in the thread as the previous posts implied HBCC might work with CF - any chance of that in the future?

You don't actually need to restart the system, to enable/disable CF.

What about the compute/gaming switch? Does Vega not need/have it or do I have an issue with my system?

Thanks!

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amdmatt
Community Manager
Community Manager

Re: Crossfire RX Vega 64 - Prim shaders - HBCC

Due to the way AFR/CrossFire works, i doubt it will ever work.

Unlike previous products, Vega is already optimised so does not need a toggle to perform better in compute apps.

nemesis_ie
Adept II
Adept II

Re: Crossfire RX Vega 64 - Prim shaders - HBCC

Thanks Matt, catch you later at OCUK.