AMD GPU Issues - Nanite in 5.1.1

Development Rendering
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1

Good Morning.

We shipped our project yesterday (yay). Since then we’ve recieved numerous bug reports from our users reporting using AMD GPUs that mesh faces are missing and/or flickering.

The project is built in UE5.1.1. It utilizes Nanite as much as possible. Lighting is completely static, with reflection captures used. We use virtual lightmaps, and virtual texturing.

Currently we have confirmed this issue to be on the following cards:
RX 580
AMD Radeon Pro 555x (running bootcamp)
RX Vega 11
RX 6500xt
RX Vega 56

I understand Nanite requires DX12 and SM6. Does it require a specific Directx feature level, or is 12_0 sufficient?

Would software play a role? Is anything other than windows and graphics drivers required to be up to date? Is windows 10 sufficient, or does it need to be 11 in certain cases?

We require a fairly large static mesh memory budget, some of these cards may be exceeding it, but my experience is that normally the VRAM overflows into system RAM and continues to work as expected. Perhaps this is not the case with AMD. Is this behaviour consistent with a lack of VRAM, or should a crash be expected?

Any additional information would be very helpful.

Thanks!

2

The same problem is being reported with a demo by the Titanic Honor and Glory team. This is what it looks like on my RX 480:

unknown_2023.03.04-20.16
unknown_2023.03.04-20.161920×1200 113 KB

So far nobody has reported a solution to the problem, so I will keep an eye on this thread.

3

Thanks, but that’s what I’m talking about. I’m the lead dev on the THG project :smiley:

4

Oh, lol. I had been hoping it was an independent report of someone else having problems :slight_smile:

Do you know whether the RX 5700 XT has the issue? It was one of the cards I was looking to upgrade to, but if it won’t help then there is no point in doing that.

5

I’d probably just avoid AMD. Doesn’t look like Epic/AMD have done a lot of work together, too many issues imo.

6

I have reports from users that AMD driver version 23.7.1 has fixed this issue. If anyone else experiencing this issue could confirm that, I’d be grateful.