RX 580 - Green sparkles on display > 1080p

[imrazor]

I've got a strange problem with the new reference RX 580 that came with my Dell Inspiron Gaming 5675. When connected to a 1080p display via HDMI, there's no problem at all. However, when I connect it via an active DP->Dual link DVI adapter to my Dell Ultrasharp 30" @ 2560x1600p, I started seeing green sparkles, especially during video playback. At first I thought it was the monitor, so I swapped it out for my old 24" Planar monitor and the problem went away. But then just to be sure I swapped in a GTX 970, and saw no problems on the 1080p or 1600p displays.

I then thought it might be the active DVI adapter. So I hooked it to DP port on the 970 and ran it that way for several days without seeing a problem. So that leaves me with an issue with the video card. Is my analysis correct? Is there any further testing I can do to be sure? What's weird is that I do not see any graphical artifacts at 1080p....

 

[InvalidError]

If your UltraSharp 30" has a DP input, use that and see if the 'sparkles' go away. If they do, then your problem is simply that two or more components of your RX580 + whatever cable + DVI adapter + US30xx combo doesn't like each other - at least not at higher signaling bit rates that come with higher resolutions and refresh rates.

If you tried the exact same setup with the GTX970 and it worked properly, it could be that the GTX970's DisplayPort has better tolerances than the RX580 and that allows it to work with a sub-par cable and/or DP-DVI adapter.

 

[imrazor]

This Dell monitor is "connectivity challenged". It has exactly one dual-link DVI port - that's it. To compensate, I'm using a mechanical dual-link DVI switch (which effectively gives me two DVI ports), to which is connected the DP->DVI adapter, which then connects to the DP on the RX 580. And of course the RX 580 has NO DVI port, single or dual link.

I'd hate to give up this monitor. The picture is the brightest and sharpest I've ever seen on a monitor. Even better than the 4K 43" Dell monitors we use at work.

I guess the thing to do is make the chain as simple as possible and take out the mechanical DVI switch. Right?

 

[InvalidError]

I guess the thing to do is make the chain as simple as possible and take out the mechanical DVI switch. Right?

Mechanical switch? Yeah, that might be a problem. Unless the switch has been exceptionally well engineered, I doubt mechanical switches are much good at maintaining signal integrity at the bit rates required for 1600p60.

 

[imrazor]

Well the switch is marketed specifically as a dual-link switch, which means it *should* be well engineered. I'm testing now without the switch in the chain, but it may take a few days to be sure the sparkles are gone. They come and go. I need more than one input for the Windows VM I'm running on this PC. Manually re-plugging the connector every time I want to use Windows would be a drag.

 

[InvalidError]

Well the switch is marketed specifically as a dual-link switch, which means it *should* be well engineered.

Maybe. I wouldn't hold my breath. There are six high speed (~1Gbps) differential pairs going through the switch and maintaining signal integrity through a mechanical switch is more challenging than it sounds.

 

[RobCrezz]

Something like this should work I would have thought?
https://www.scan.co.uk/products/club-3d-displayport-to-dvi-d-dual-link-330-mhz-active-adapter?gclid=CjwKCAjw6djYBRB8EiwAoAF6oYxrOSsqv_rIBQvwQWk0AwEqgQUbJ1S5h8Ff1R6PHtwBiHfvwCMYyhoCE_UQAvD_BwE

 

[InvalidError]

Something like this should work I would have thought?
https://www.scan.co.uk/products/club-3d-displayport-to-dvi-d-dual-link-330-mhz-active-adapter?gclid=CjwKCAjw6djYBRB8EiwAoAF6oYxrOSsqv_rIBQvwQWk0AwEqgQUbJ1S5h8Ff1R6PHtwBiHfvwCMYyhoCE_UQAvD_BwE

OP has a DVI-D only 1600p display and is already using a converter. His problem appears to be that he's using a mechanical DVI switch to mux multiple DVI display sources and the switch might not be good enough to maintain signal integrity. At least not with the DP-DVI converter when connected to his RX580.

 

[RobCrezz]

Something like this should work I would have thought?
https://www.scan.co.uk/products/club-3d-displayport-to-dvi-d-dual-link-330-mhz-active-adapter?gclid=CjwKCAjw6djYBRB8EiwAoAF6oYxrOSsqv_rIBQvwQWk0AwEqgQUbJ1S5h8Ff1R6PHtwBiHfvwCMYyhoCE_UQAvD_BwE

OP has a DVI-D only 1600p display and is already using a converter. His problem appears to be that he's using a mechanical DVI switch to mux multiple DVI display sources and the switch might not be good enough to maintain signal integrity. At least not with the DP-DVI converter when connected to his RX580.

Yeah I get that. Thats why I suggested the above converter which supports DP to Dual Link DVI with his resolution.

 

[imrazor]

@RobCrezz I'm already using this adapter: http://www.dell.com/en-us/work/shop/dell-adapter-displayport-to-dvi-dual-link/apd/470-aanw/tv-home-theater
The mechanical switch I bought is this one: https://www.amazon.com/gp/product/B000GTLFS6/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1
I know its a no-name brand, but I had a really hard time finding one that wasn't an expensive KVM. If someone has another idea, I'm open to suggestion, BUT I don't want a KVM. I'm working with a virtual machine that requires that the keyboard and mouse stay connected, even when the monitor input is switched to the host.

@InvalidError I've tried simplifying the chain to RX 580+DP->DL-DVI+monitor. It's only been a few hours, but so far no green sparkles. They're very intermittent.

As an aside, instead of the switch being the problem could it simply be the amount of cabling involved? If I got some very short, heavily shielded cables, might that fix the problem?

One other note. I *do* get green sparkles with the GTX 970, but only if the refresh rate is set to 60Hz. If I drop the refresh to 59.9Hz the green pixels go away, and stay gone. Dropping the refresh rate to 59Hz does *not* fix the problem on the RX 580+adapter+switch.

 

[InvalidError]

From the switch's Amazon page: " Maximum Video Resolution: 1080p"

Using higher quality cables MIGHT help and since you already have those cables, may as well try them. But that doesn't change the underlying fact that the switch's seller hasn't "specified" it beyond FHD resolution. From how generic it looks, I'd be surprised if it passed any sort of formal HDMI signal integrity testing.

I wouldn't be surprised if part of your "sparkles" issue is dirt or other contaminants in the switch's contacts or just weak contact force.

 

[imrazor]

Damn. I would've sworn I researched the heck out of that switch and it supported dual-link DVI @ 1600p - or at least 1440p. Could they have changed the description since I bought it? I suppose it doesn't matter now anyway...

I've been using the RX 580 for several hours now, and so far no green pixels. Since they're intermittent, I'll need to test it for a few more days to be sure.

 

[imrazor]

I wanted to add a second graphics card, and go back to muxing them, so I switched to the 970 and used straight DVI->switch->monitor. It worked fine for a couple of days, but one day I went to switch inputs and the green pixels came back. So it does seem to be the switch. I was able to restore a clear picture by toggling the switch a couple of times, something I was unable to do with the RX 580.

I'm just not sure where I can get a tested and certified mechanical dual-link DVI switch. Pretty niche, I guess.

 

[InvalidError]

I'm just not sure where I can get a tested and certified mechanical dual-link DVI switch. Pretty niche, I guess.

A mechanical switch capable of properly handling 6x500Mbps differential signals would be a very precise (read: expensive) piece of engineering. Maintaining signal quality is much easier with electronic switching, generally in the form of a KVM switch.