I bought a 980 Ti and 4K monitor specifically to play Fallout 4. The launcher recommended Ultra settings and it performs fine, but in many game areas at certain times of day, the game keeps switching to a black screen every few seconds, making it unplayable. After a lot of experimenting I've isolated it to when there are lots of trees visible in daylight (i.e. heading south out of the Westing Estate at 10am), so I think it must be a lighting problem on those scenes. It doesn't seem to be a monitor or a heat issue, the engine is literally outputting black. Only switching to non-native resolution seems to stop it happening, but that looks awful on this monitor and would mean I wasted ￡1000+, so I'd really like to sort it out!

In terms of other info:

• If I turn the settings down to Low in the launcher and keep the resolution at 4K, it still happens!
• If I look at the floor, the switching seems to stop; look up, it comes back again.
• Returning to the same spot at night avoids the problem.
• I'm running Windows 10, and connected via DisplayPort.

Has anyone seen a problem like this? Any recommendations on settings I can tweak that might control how trees are lit/shaded? Thanks!

Is there a setting for Shadows on leaves or vegetation?

When you got your video card, did you get the latest drivers from Nvidia, or use the disk that came with the card? If you just used the disk, update your drivers, Nvidia has done a few updates just for this game.

On a side note, the Nvidia Experience is a known problem for this game. If you get crashes and weirdness, the first thing to try is to disable that program.

What happens when you set the resolution to a lower setting like 1080p or 720p just for testing.

I can't find a setting specifically for shadows on vegetation? I just tried setting Shadow Quality to Low and Distance to Medium, it didn't stop the black screen though.

I'm using the latest NV drivers (359.06), I never put the bundled disk in. I haven't used GeForce Experience either, everything is vanilla at the moment.

Dropping to a lower resolution fixes it immediately! However, as it's non-native, it looks atrocious on this panel, it's pretty much the only thing I can't do.

Maybe there is something that can be modified in the ini files for the trees.

What setting are you using for god rays and are you using AA, AF SSAO settings and what are they.

What's the make and model of the monitor?

Is the cable a mini displayport to displayport or regular displayport?

Use msi afterburner to log VRAM use during Fallout 4.

I started out with:

• Godrays: High
• AA: TAA
• AF: 16 Samples
• AO: SSAO (High)

I then tried:

• Godrays: Off
• AA: Off
• AF: Off
• AO: Off

And it still happens!

I am using an Iiyama ProLite X4071UHSU (basically the same as the Philips BDM4065UC). It's connected via fullsize DisplayPort 1.2.

VRAM use is hovering just below 3.5GB, out of 6GB available.

It could still be the cable, 4K @ 60Hz is maximizing the bandwidth.

You can try another DP connection on the graphics card (you should have 3 DP connections. You can try dropping the refresh rate down to 30Hz (for troubleshooting purposes). You can try using the HDMI connection (still allows 4K @ 60Hz, in port 1).

I wondered about the cable too. By way of comparison, I just tried pushing Far Cry 4 through it instead for half an hour at the same settings (4K/60Hz), and didn't see a single glitch. Does that validate the cable?

Unfortunately the other DP connections are taken, but as it happens they're all the same (I have 3 identical 4K screens), so I was able to try every combination of port, monitor and DP cable, and all of them exhibit the same problem, although it feels like some combinations get it worse than others. Fallout 4 is absolutely rock solid in the cities, even at the top of a skyscraqer looking for miles. Could cables at the same resolution/refresh start to fail according to what's being shown on-screen? Does bandwidth go up on a detailed scene somehow? Interestingly, 30Hz improves it a bit (it blacks out less) but the problem hasn't gone away.

Okay, probably not the cable then.

Are all 4K monitors active when playing Fallout 4 (not necessarily displaying Fallout 4)? You could be over-stressing the 980 Ti even if its not rendering on all displays. Farcry 4 is probably less taxing on the 980 Ti then Fallout 4.

That's a good point - they weren't doing much but they were active, and a desktop resolution of 11520x2160 probably isn't very kind. I've just tried disconnecting them to get it down to a single 4K screen and the problem remains.

Any way to post a video of the symptoms?

I might be a bug with the engine. Doesn't make me want to buy a 4K monitor

Funnily enough, I was just trying to get ShadowPlay recording to see if the blackouts were on there too. I can record something with my phone, but it won't be very enlightening, it'll just be normal gameplay where suddenly the screen blacks out and the sound/game keeps going. After a few seconds it'll pop back for a moment, then disappear again. I can sort of control it by looking at or away from trees.

And yeah, having moved up from triplehead 30" (2560x1600), I'm finding 4K a terrible experience. You're at the limit of so much existing technology that you hit bugs and limits everywhere. Reliable cables are hard to find, Windows starts to break in unexpected places, game support is hit and miss.

SOLVED. It was the cables! Replacing my ￡15 cables with ￡50 ones stopped this happening. I wouldn't have thought it possible, but it seems high detail scenes somehow put more stress on the cable, and cause it to blank out. Maybe they need higher bandwidth than simple scenes because DP uses packets?

Is your new cable HDMI 2.0 and the old one a version 1? Those only have so much bandwidth and if you try 4k some only do 30hz, some can do 60 but with lower colours. It's probably something to do with the latter.

HDMI 1.4 can only transfer at 10Gbps. 2.0 has 18Gbps. That's a massive difference. Higher frequency allows more data to be transferred. It's likely F4 has a high bandwidth requirement due to the high hardware requirements and their models/textures and post processing effects combined with the pixel count.



Edit

I'd predict that there would be a noticeable performance benefit between GPU in PCI-E 2.0 and 3.0.

Nope, as I said, all connected via DisplayPort. The cables were supposedly rated for 4K, but I wasn't convinced as they didn't look thick enough. DisplayPort is a relatively weak signal compared to HDMI (only 3.3v) so I guess it's much more dependent on cable quality. Can't say I like it much; if my card had three HDMI 2.0 outputs I would have much preferred to use those.

Ah OK cool I'll keep that in mind as I don't like using HDMI.