Your UE 5.4 sounds corrupted or you have some kind of overlay / benchmark software that is wrecking the performance. Any type of FPS or software overlay will affect its performance. I found that out the hard way when I discovered Riva Tuner running in the background messing with it.
was this reported using the bug report tool? same is happening for me on 5.3.2.
Actually game thread and RHIT are parallel in editor for 5.3 and then it fails to do that in packaged project.
How can we get a dev to look at this, it’s a huge performance problem but clear that it works totally fine in-editor as far back as 5.3 so like what’s the issue here
@skfabby sorry to ping you, just wondering if there is a way to pass the replied threading issue on to relevant team as this is a serious engine issue affecting performance across many platforms
Same issue for me on RTX4080 and RTX3080
I’ve passed your message on. 
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Thanks so much 
I had reported the same issue here also before realizing others were having the same problems:
And for me, even as far back as 5.3.2 RHIT runs parallel to Game Thread in-editor:
But in the packaged game (both shipping and development) they run sequentially, meaning that packaged projects run about 30% slower than projects in-editor simply because RHIT won’t run in parallel:
You can see the frame time is about 4ms worse in packaged projects because of this issue.
Parallelization was listed on the roadmap for the 5.4 Release, so I’m not sure why it works in-editor in the older engine version 5.3.2 and then not at all in packaged projects or in the later 5.4 and 5.5 releases even though this was a major selling point of those updates.
It’s also worse on some hardware than others. I have an RTX 4080 PC that suffers badly from this. On the RTX 3080 with Outdated NVIDIA Drivers installed, it doesn’t happen at all.
In theory, the 4080 should be a much faster card but the older 3080 system outperforms it significantly (90FPS on the 3080 system vs. 55 on the 4080) because of time spent waiting for RHIT to run in sequence (the above screenshots are from the 4080 system). Both PCs have Intel 12900 CPUs running on the same version of Windows 10.
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I didn’t report the issue. I once put a bit of work into reporting a bug, but it wasn’t even listed in the tracker. Not sure what happened there, but I’m not going through that process again.
I think posting an obvious UEInsight screenshot on this forum in a thread about UE’s performance should be sufficient to get the issue heard.
Usually this kind of stuff gets solved/fixed at some point and I/we have learned to be patient with UE. Despite the (many) hick-ups, UE’s still the best engine out there (by far!).
I think posting an obvious UEInsight screenshot on this forum in a thread about UE’s performance should be sufficient to get the issue heard.
I wish I had your optimism, some of these issues have been in the engine since 5.0EA which was about 3 years ago and still not addressed :'D
Just to note, @skfabby same issue does indeed appear on 5.4.4 with the RHI Interrupt and RHI Submission Threads.
Reduction in FPS from ~90 down to 37.5. Entirely attributable to these threads operating asynchronously
It happens spontaneously but as an added trigger I have found calling Load Level from Blueprint can sometimes trigger the issue. The only fix is to completely close and restart the application.
You can see here 18.9ms of Game Thread doing nothing but waiting for RHI:
For context 18.9 ms is longer than an entire frame should take.
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Hey, just adding to this.
Recently went live with a public playtest and getting massive RHI stalls for maybe 5% of players. Initially thought it was AMD cards (as they were in the majority) but also happening on NVIDIA cards.
No idea what’s causing it.
Hi, yes I agree the engine has got work over time and Epic don`t seem to be just ignoring the fact hoping it will go away! I have been using the Unreal engine for coming upto 3 years now. I noticed an issue when we moved from UE4 to UE5 in general. Inconsistent frame rates, poor performance. Unfortunately the engine has gone downhill since then and the new technologies like Lumen and Nanite still need ALOT of optimization.
I disabled virtual textures and the hitching I posted earlier seems to have gone.
Unsure as to why, will keep investigating.
Just a thought: virtual assets are streamed into the engine; usually from disk. If you are streaming from a platter-drive it can be problematic, or even a slow SSD.
Best served with an M2-level drive as the I/O speeds are an order of magnitude(s) faster.
Also, if you do not have enough RAM to store the assets, memory management will start thrashing as it has to reorder the cache, free space for new stuff, etc and spend more on overhead vs processing.
For 2025 readers.
A reminder to backup, backup, triple backup and (not a backup) version control (Git) if you take your projects seriously. Upgrading, corruption other forms of data loss is no joke.
Even UE4 was full of bugs and didn’t get the love of much required fixes. The only way to get those fixes was to move to UE5 which was a marketing move. UE5 then blew up with more experiments instead of moving to a LTS structure, which is very disappointing. Too often, 1 fix came with 5 bugs.
This cr"p causes burnout:
Also hard to work with when you are doing an X year taking project and wish to stick with a version, instead of kicking the entire framework away from underneath it halfway.
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