iMac 2020, 5700XT - graphical glitch?

[shywizard]

When i captured the horizontal line video (see page 4 of this thread), i saw several glitches in a row, so I quickly grabbed my camera and luckily caught the last one that appeared.

FYI: This was on a brand new iMac with the 5700XT graphics card that arrived today, and i just took it out of the box.
I assume your line glitches look the same? Interestingly, this didn't go across the entire screen, just behind the right side of the open window.

 

[costica1234]

When i captured the horizontal line video above, i saw several glitches in a row, so i quickly grabbed my camera and luckily caught the last one that appeared. FYI: This was on a brand new iMac with the 5700XT that arrived today, and i just took it out of the box. As the only person whose been able to capture it, i think i deserve an award??

There you go: ???.

On a more serious note, please report this bug to Apple. The more people report it, the higher the chance this bug will be fixed!

This glitch is the only reason for which I’m currently holding off on buying the new iMac (I would get the normal 5700, but still worried about a potential HW bug with these GPUs).

On a different note, is the Intel GPU so bad that it’s unable to drive a 5K display? I don’t really like the idea of having the dGPU running all the time...

 

[creativityrules]

There you go: ???.

On a more serious note, please report this bug to Apple. The more people report it, the higher the chance this bug will be fixed!

This glitch is the only reason for which I’m currently holding off on buying the new iMac (I would get the normal 5700, but still worried about a potential HW bug with these GPUs).

On a different note, is the Intel GPU so bad that it’s unable to drive a 5K display? I don’t really like the idea of having the dGPU running all the time...

There is no Intel GPU in the iMacs.

 

[creativityrules]

Searched on google for "5700XT glitch" and appears to be a constant issue with this GPU... not sure how quickly apple can fix this. Would drive me nuts if this happens on a brand new computer.

 

[kkh]

There is no Intel GPU in the iMacs.

Well, technically, there is. But afaik, the Intel one is disabled / or at least we can't manually switch to it like you could on a MBP.

AGDCDiagnose Version: 5.2.6.6
### Start: GPUWrangler #######################################################
Stats: GPUCAdded:1 GpuAdded:2 Eject:0/f0/fd0/c0 Remove:0/t0 Un:0

gpu 0xd1c flags 0xb2000010 (IG,published,quiet,pubSched,pubArmed) vid.did=8086.9bc5 b:d:f=0:2:0
gpu 0x0d1c pci 0x100000201 IOService:/AppleACPIPlatformExpert/PCI0@0/AppleACPIPCI/IGPU@2
gpu 0x0d1c agdc 0x1000005bd /AppleIntelFramebufferController/IntelFBClientControl
gpu 0x0d1c gpuc 0x000000000
gpu 0x0d1c agdpclient 0x000000000
gpu 0x0d1c accel 0x1000005b9 /IntelAccelerator

gpu 0x88e5 flags 0xbe000020 (DG,published,driversStarted,hasGPUC,quiet,pubSched,pubArmed) vid.did=1002.7319 b:d:f=3:0:0
gpu 0x88e5 pci 0x1000001fe IOService:/AppleACPIPlatformExpert/PCI0@0/AppleACPIPCI/PEG0@1/IOPP/EGP0@0/IOPP/EGP1@0/IOPP/GFX0@0
gpu 0x88e5 agdc 0x100000618 /AMDRadeonX6000_AmdAgdcServices
gpu 0x88e5 gpuc 0x100000595 /AMDRadeonX6000_AmdGpuWrangler
gpu 0x88e5 agdpclient 0x10000061a /AMDRadeonX6000_AmdAgdcServices/AppleGraphicsDevicePolicy/AGDPClientControl
gpu 0x88e5 accel 0x1000005fb /AMDRadeonX6000_AMDNavi10GraphicsAccelerator
gpu 0x88e5 fb0:0 0x1000005fd /AMDRadeonX6000_AmdRadeonControllerNavi10/ATY,Ikaheka@0
gpu 0x88e5 fb1:1 0x1000005ff /AMDRadeonX6000_AmdRadeonControllerNavi10/ATY,Ikaheka@1
gpu 0x88e5 fb2:2 0x100000602 /AMDRadeonX6000_AmdRadeonControllerNavi10/ATY,Ikaheka@2
gpu 0x88e5 fb3:3 0x100000605 /AMDRadeonX6000_AmdRadeonControllerNavi10/ATY,Ikaheka@3

### End: GPUWrangler (took 0.118 sec) ########################################

 

[costica1234]

There is no Intel GPU in the iMacs.

I think all the Intel chips inside iMacs come with UHD 630 graphics (the i9 in the 2020 iMac surely has it based on what I am seeing on Wikipedia). But regardless of whether the iGPU is there or not, would the UHD 630 be unable to drive a 5K display? This is what I asked in the above.

 

[kkh]

Searched on google for "5700XT glitch" and appears to be a constant issue with this GPU... not sure how quickly apple can fix this. Would drive me nuts if this happens on a brand new computer.

Yes, that's the 5700 XT (the PC version of this card). For the iMac specific one, the "Pro" 5700 XT, these issues aren't really widely reported yet it seems.

 

[kkh]

Have actually never had issues with any of the Nvidia cards on my Macs. The last time I had a video card issue, it was an AMD card also. Many PC gamers seem to have completely switched camps from AMD to Nvidia after the continuing (a decade by now) driver issues. Was hoping they'd do better with these iMac specific cards.

 

[kkh]

Would drive me nuts if this happens on a brand new computer.

Driving me nuts for sure. Taints the experience for sure and affects Apple's reputation every time it happens. I assume that these days all the components for something like an iMac come together so late in the game that there is minimal to no time for testing before it heads out to us.

 

[Whiteman007]

@shywizard alos I’m using 2 monitors and haven’t noticed any issues described in this thread

 

[torifile]

@shywizard alos I’m using 2 monitors and haven’t noticed any issues described in this thread

That's 2 of us. I previously had the glitch running with the internal display only and it hasn't happened since Saturday when I got my USB-C to Displayport cable and hooked up my 2nd display. I'd be interesting to hear others' experience with 2nd displays.

 

[torifile]

There you go: ???.

On a more serious note, please report this bug to Apple. The more people report it, the higher the chance this bug will be fixed!

This glitch is the only reason for which I’m currently holding off on buying the new iMac (I would get the normal 5700, but still worried about a potential HW bug with these GPUs).

On a different note, is the Intel GPU so bad that it’s unable to drive a 5K display? I don’t really like the idea of having the dGPU running all the time...

Why on earth, when battery isn't a concern, would you have any objections to using a dedicate GPU all the time?

 

[costica1234]

Why on earth, when battery isn't a concern, would you have any objections to using a dedicate GPU all the time?

Thermals is the #1 reason. Secondly, the dGPU is more likely to fail if it keeps running all the time... I want to be given the option to run the dGPU only when needed!

 

[torifile]

Thermals is the #1 reason. Secondly, the dGPU is more likely to fail if it keeps running all the time... I want to be given the option to run the dGPU only when needed!

That sounds like a whole lot of hand-wringing. If you're doing a task that an integrated GPU is sufficient for, a dedicated one won't break a sweat and thermals won't be a concern.

Similarly, a task that can be handled by an iGPU won't tax a dGPU to the point of failure. If a dGPU fails because it's having to do the work an iGPU could have handled, it was going to fail anyway.

Honestly, this is a lot like saying you don't want wireless keyboard/mouse because charging them taxes the USB bus occasionally.

 

[creativityrules]

Thermals is the #1 reason. Secondly, the dGPU is more likely to fail if it keeps running all the time... I want to be given the option to run the dGPU only when needed!

I think Apple would want you to buy a new iMac when the GPU dies... or consider fixing it for about ¼ the cost of a new one

 

[costica1234]

My observations come from using a mid-2015 MBP. The dGPU can kick in at random times and the laptop gets really hot even when doing light work!

Now I get it that the iMac might cope better with this since the cooling is improved compared to an MBP (not ideal though), but I still preferred to have the iGPU in addition to the dGPU.

 

[kkh]

That's 2 of us. I previously had the glitch running with the internal display only and it hasn't happened since Saturday when I got my USB-C to Displayport cable and hooked up my 2nd display. I'd be interesting to hear others' experience with 2nd displays.

This is fascinating. Curious if turning the external display off would make the glitches come back? Or do you have to physically unhook the display so you have no Displayport cable attached.

So, this is like the card saying: "Oh man, I can do so much more than drive a single display! Come on! Give me a second screen to play with!".

 

[torifile]

My observations come from using a mid-2015 MBP. The dGPU can kick in at random times and the laptop gets really hot even when doing light work!

Now I get it that the iMac might cope better with this since the cooling is improved compared to an MBP (not ideal though), but I still preferred to have the iGPU in addition to the dGPU.

That dual GPU setup was seen largely as a debacle and it was designed with the dual GPUs as a way to maximize battery life, not longevity. I wouldn’t want that setup in a desktop. Ever.

 

[pollaxe]

That's 2 of us. I previously had the glitch running with the internal display only and it hasn't happened since Saturday when I got my USB-C to Displayport cable and hooked up my 2nd display. I'd be interesting to hear others' experience with 2nd displays.

I'm using my (5700XT) iMac with two external displays - a Wacom Cintiq 27 QHD and a BenQ PD2720U monitor - and I haven't noticed any graphical glitches. However, I only spotted this thread yesterday and I had the two screens wired-up to it pretty quickly after the initial set-up. Therefore, the majority of my use has been with the three screens.

The BenQ is running via a TB3 cable and the Wacom is running from a USB-C to Displayport cable.

Edit: my iMac is an i9 from Ireland.

 

[joevt]

I was able to capture the white horizontal line in the initial setup screen

Is it a coincidence that the line appears near the bottom edge of the window?

It makes sense that the line is only half the width of the screen, since 5K iMac displays use two different DisplayPort signals - one for each half (left half and right half) of the display. Does the glitch appear on just the right side of the display or on either side?

I think all the Intel chips inside iMacs come with UHD 630 graphics (the i9 in the 2020 iMac surely has it based on what I am seeing on Wikipedia). But regardless of whether the iGPU is there or not, would the UHD 630 be unable to drive a 5K display? This is what I asked in the above.

The UHD 630 could drive the 5K iMac display because each half of the display only requires DisplayPort 1.2. Intel GPUs can only drive 3 displays, so you would only be able to connect one 4K display with the 5K display.

 

[shywizard]

Is it a coincidence that the line appears near the bottom edge of the window?

It makes sense that the line is only half the width of the screen, since 5K iMac displays use two different DisplayPort signals - one for each half (left half and right half) of the display. Does the glitch appear on just the right side of the display or on either side?


The UHD 630 could drive the 5K iMac display because each half of the display only requires DisplayPort 1.2. Intel GPUs can only drive 3 displays, so you would only be able to connect one 4K display with the 5K display.

I have two iMacs with the 5700XT. Not kidding, one glitches to the left side of the screen, the other to the right side of the screen. STRANGE!

 

[PieTunes]

It's probably not related, but just idle curiosity here. My 5700XT iMac was made in Ireland, and I experienced the white flashing lines. Others who have seen them, where did your custom iMac hail from, China or Ireland?

 

[haddy]

I have two iMacs with the 5700XT. Not kidding, one glitches to the left side of the screen, the other to the right side of the screen. STRANGE!

Does it make a difference if you have an i9 or i7, ie 8 v 10 cores?

 

[ADGrant]

I have two iMacs with the 5700XT. Not kidding, one glitches to the left side of the screen, the other to the right side of the screen. STRANGE!

That is a bit worrying. Suggests it might be hardware related. Is this behavior consistent across reboots? Are the Macs next to/close each other or in different parts of your house.

 

[Nermal]

Also, to confirm: my machine with this issue came from Ireland. Apple seems to be assembling these machines in both China and Ireland. Luck of the Irish?

It's probably not related, but just idle curiosity here. My 5700XT iMac was made in Ireland, and I experienced the white flashing lines. Others who have seen them, where did your custom iMac hail from, China or Ireland?

Mine's from China.