[Sticky] Radeon RX 6800 / RX 6800 XT / RX 6900 XT for macOS -> AMD Navi RDNA2 Support added in 11.4 Beta
Where did you read that? Is there any other information?
Surf, drums, Java/script
thanks for your help. From the Mac system report:
(after comes the AGDCDiagnose report)
The AGDCDiagnose has the EDID for Samsung TV with product ID 703F, but the log shows that product IDs 703E and 7040 also exist. Those other two may be for different ports of the TV (or different settings) and may have other different EDID info.
The TV is using an HDMI connection (no DisplayPort info). I can't tell if the connection is working as HDMI 2.1 because it's only using 4K60 HDMI 2.0 timing (10bpc HDR 4:2:0). You appear to be using a 8K scaled HiDPI mode (Looks like 4K) that is scaling down to 4K in the GPU. That may be redundant. Or you need to change the "Scaled resolutions base" option in SwitchResX to 7680x4320? Well, no point doing that until you can confirm a working 8K timing.
Regarding the EDID for 703F, It does include 8K timings (not custom timings - these are VIC codes from CTA-861 spec) up to 60Hz but in the EDID base block, it has a limit of 1190MHz which is only good enough for 30Hz - it should be 2376MHz for 60Hz. The horizontal limit is 255kHz which is good enough for 50Hz but should be 270kHz for 60Hz. SwitchResX has options for overriding the frequency ranges. Check the current values, post a screenshot. Maybe override them if the ranges are lower than needed for 8K60.
The EDID shows that the HDMI port supports HDMI 1.4 and HDMI 2.0 links (3 lanes, 3.4 Gbps and 6 Gbps each) and HDMI 2.1 links (4 lanes, 6, 8, 10 Gbps but not 12 Gbps).
HDMI 2.1 (10 Gbps/lane) modes (assuming HDMI timings, no DSC):
- 4K60 16bpc 4:4:4 (but the EDID has no mention of anything greater than 10bpc)
- 4K120/8K30 8bpc 4:4:4, 10bpc 4:2:2
- 8K60 8bpc 4:2:0
DisplayPort 1.4 modes (assuming HDMI timings, no DSC):
- 4K60 12bpc 4:4:4 (but the EDID has no mention of anything greater than 10bpc)
- 4K120/8K30 10bpc 4:2:0
- 8K60 6bpc 4:2:0 (Macs don't support 6bpc, 4:2:0 doesn't support 6bpc)
I'm not sure if DSC is supported. Certainly the card supports it but I'm not sure about the OS and the driver. The CAC-1085 will be limited if DSC is not used. AGDCDiagnose can definitely tell if DSC is used in the DisplayPort case but the HDMI 2.1 case is new to me - I won't know if it supports DSC unless someone shows that it does. Big Sur has an issue where it doesn't always use DSC where Catalina would use DSC, but you can't use the Navi21 cards with Catalina so that can't be tested...
When you install SwitchResX, enable "Show best resolutions for display in bold". These are the non-scaled modes which are actual timings. For each timing, there should be a HiDPI mode and a non-HiDPI mode (otherwise known as a low-resolution mode).
@reinhard1004, I already installed 11.4 beta 2 and still no support for RX 6700XT. Only 6800, 6900 and 6900XT are supported for the time being. We'll need to wait a bit. Maybe in later beta versions the support for our card is added. I would not expect that a particular model like ours is forgotten in the bin.
9to5mac says 11.4 beta 3 is supposed to be out. Any chance you've tested it with a 6700xt yet?
@norcom, as far as I see, it's not out yet, but be sure I'll test it as soon as possible and keep it posted here.
Surf, drums, Java/script
I upgraded to the latest MacOS 11.4 beta 3 that came out today, and I installed SwitchResX. From the SwitchResX menu, there seams to be many resolutions (hundreds) to choose from. The Display control panel doesn't show the 8K options still.
Now 8K@60hz seams to work smooth on the 2018 Mac Mini with AMD 6800 XT, with the Samsung Q800T 8K TV, a first time for me. Text and menu bar appear unbelievably small. I will send screen dumps from SwitchResX and EDID info etc tomorrow. I'm not sure what Chroma subsampling is used and/or DSC, but text is not as crisp/sharp per pixels as with standard lower resolution monitors. Could be the Samsung or the sampling/transfer.