Unreal Engine 5.4: Epic's latest revision delivers big performance and feature wins
Alex Battaglia investigates Unreal Engine version 5.4. What new additions and improvements are there, and how will games make use of them on PC and consoles?
www.eurogamer.net
Here we go. UE5.4 performance improvements video.
- Massive 45% improvement on PC's best CPU 7800x3D going from 5.0 to 5.4.
- Console CPU (XSX CPU from China) sees a 60% improvement while walking, 80% while flying.
- Big Upgrades to Reflections and Emissive Lighting in Lumens. Reflections can now display more colors and materials. Emissive lighting has better GI coverage.
- Shader compilation has improved on PC thanks to the auto UE5 shader compilation feature. But it's still not good enough and devs still need a shader compilation step to iron out the remaining stutters.
From article...
Enter Unreal Engine 5.4. There are a fair few changes here, but the biggest and most imporant change is renderer parallelisation - essentially splitting up the render thread to better utilise multi-core CPUs. This change has a profound impact on performance when comparing Unreal Engine's city benchmark between versions 5.0 and 5.4. In a CPU-limited scenario on a Ryzen 7 7800X3D, the frame-rate is 42 percent higher in 5.4.
Put another way, you're going from having basically no chance to see 60fps on one of the best gaming CPUs - one that wasn't even available when the first UE5 demo launched! - to easily pushing frame-rates into the 80s. That's a huge improvement to overall performance, despite the content and settings remaining the same, and it's predominantly down to that better CPU utilisation.
That's great news for PC, but it's also a boon for consoles. While we can't run the UE 5.4 demo on consoles directly as we can on PC, we can use our Frankenstein PC to get a sense of how current-gen console-equivalent hardware fares. This PC is equipped with an AMD RX 6700, a graphics card close to that in the PS5, and a 4800S desktop kit, which is the actual APU from the Xbox Series X. That mish-mash theoretically ought to deliver performance in the same ballpark as a current-gen console, but in reality frame-rates are far below what we'd imagine on 'epic' settings.
Regardless, we get a 60 percent average frame-rate uplift when running through the streets going between versions 5.0 and 5.4, complete with much less spiky frame-times as we start to become GPU limited. When flying through the city, stressing the CPU more, that differential shifts to 80 percent. While this test isn't indicative of actual console performance then, it does show that the UE version improvements help lower-end configurations more than higher-end ones, relatively speaking.
While Unreal Engine 5.4 does show convincing average performance gains, the engine still has some way to go in terms of other performance scenarios. As I've pointed many times in Digital Foundry articles, UE has a big shader compilation stutter issue. There are a lot of reasons for this, but you can see the issue big-time when you first run the Matrix city sample in version 5.0 - massive frame-time spikes into the hundreds of milliseconds. To fix this, developers tend to use a manual shader precompilation step, but this is labour-intensive for the developer to prepare and requires a thorough approach to pick up all shaders.
It's evident that Unreal Engine 5.4 is an significant release, particularly if that circa 40 percent CPU performance we saw in the Matrix demo is anything like indicative of the sort of uplift we might see in shipping games. And, as we saw elsewhere, UE 5.4 is better-looking than 5.0 in many areas, especially using the higher quality presets made for PC graphics cards.
It's equally clear that UE would also benefit from further performance improvements, specifically with regard to frame-time stability. Shader caching still needs work too, if Epic's own game Fortnite is an accurate measuring stick - a game like this shouldn't stutter so badly on a high-end CPU. I'd like to see a more systemic approach to alleviating traversal stutters too, as these are found all over the Matrix demo and almost every UE5 game out there.
*Credit to Slimy on gaf for brief synopsis.
Last edited:
