The visual differences are real, but hard to prefer one version to another. Perhaps with a few more months of work, the version under Unreal Engine 5 will eventually surpass that under Unreal Engine 4.
We have seen this through several demos, Unreal Engine 5 offers many visual improvements over the Unreal Engine 4. The latest version of the engine from Epic Games notably benefits from a completely redesigned lighting system supported by Lumen technology. The game Fortnite, recently moved to Unreal Engine 5.1, provided a good overview of earnings. There is another production, unofficial this time – and which is also not supported by an armada of developers – which also made its transition from Unreal Engine 4 to Unreal Engine 5: the fan remake of The Legend of Zelda: Ocarina of Time made by CryZENx. The video below, offered by the SiNKiLLeR channel, offers a direct comparison between the two versions.
In the case of this remake, it must be recognized that we would have a hard time favoring one version over the other. If the version under Unreal Engine 5 benefits from more realistic light effects, it also loses some of the cachet of the version under Unreal Engine 4. Well, in defense of CryZENx, he probably has not yet had the leisure to fine-tuning his new version: while he spent six years on the Unreal Engine 4 edition, he only carries its remake in the Unreal Engine 5 for a few months.
And in the case of Fortnite?
As mentioned at the beginning of the article, in the case of a large production like Fornite, the Unreal Engine 5 is very beneficial. To convince you, you can watch the sequence below, proposed by Digital Foundry. It does not directly compare the Unreal Engine 4 and Unreal Engine 5 versions, but illustrates the contributions of Nanite and Lumen.
Source: SiNKiLLeR via DSOGaming