Lego Batman: Legacy of the Dark Knight Looks Like a PC Performance Disaster

Since Nvidia launched frame generation with the RTX 4080, I've been waiting for a developer to make it a requirement for acceptable performance. Almost four years later, Lego Batman: Legacy of the Dark Knight appears ready to cross that line.

TT Games dropped the system requirements this past weekend. They look reasonable for an Unreal Engine 5 game at first glance. Look closer and you'll see the company wants frame generation enabled just to hit 30 fps on minimum settings. That's not how frame generation works.

If this isn't an error, minimum spec hardware will only reach 15-20 fps without frame generation. At that point, AI-generated frames won't save it from being unplayable.

What is Frame Generation For?

Frame generation looks like a magical performance boost. Understanding why leaning on it to hit 30 fps is bad requires knowing how it works.

Frame generation uses machine learning to create frames based on a rendered frame and motion vector data from the game engine. While your GPU generates this frame, the actual rendered frame waits. Then both the original and generated frames get paced out by your CPU or GPU.

This process introduces latency. At higher frame rates, the added latency is barely noticeable. There's a reason AMD and Nvidia both recommend enabling this feature only when you're already hitting decent frame rates – at least 30 fps, preferably 60 fps or above. At lower frame rates like the 15 fps these Lego Batman requirements suggest, you're already dealing with extreme latency. Frame generation makes it worse, even if it looks smoother.

At lower frame rates, there isn't enough data from rendered frames and motion vectors to accurately generate extra frames. The lower your frame rate when you enable frame gen, the more artifacts and visual glitches you'll see.

Too early to know whether Lego Batman: Legacy of the Dark Knight will actually run this poorly without frame generation. But if it does, playing this game will be terrible unless you have a powerful enough gaming PC to brute force good performance.

Frame Gen with Old Hardware

It gets weirder. TT Games requires at least an Nvidia GeForce GTX 960 to run Legacy of the Dark Knight. That would be a modest spec on its own. But even with this ancient graphics card, it's still recommending frame generation – except DLSS frame gen doesn't work on GPUs this old.

For these older GPUs, TT Games is relying on FSR or XeSS frame generation. These work much like Nvidia's tech, but they're not accelerated by specialized GPU cores. They're slower and less accurate. A bad performance situation just got worse.

Crimson Desert was another game that relied on FSR frame generation to boost performance on handhelds like the Steam Deck or Xbox Ally X, but that game used this technology to reach 60 fps, not 30 fps.

TT Games doesn't even mention handhelds in the system requirements for Legacy of the Dark Knight. Safe to assume this game won't run well on portable systems. That's a shame, because it's the type of game that'd be great to pull out on the train or on a long flight.

A Bad Port in a Sea of Good Ports

What's wild about Lego Batman: Legacy of the Dark Knight having such ridiculous PC requirements is that the best PC games this year have been extremely well optimized. Crimson Desert, Resident Evil: Requiem and Pragmata have all run like a dream. None of these games are running on Unreal 5, which makes the latest Lego game stand out even more.

Worse, these Lego games are designed for kids. Sure, some kids have parents with expensive rigs, but these inflated system requirements could place the game out of reach for many.

Based on the previews we've seen, Legacy of the Dark Knight does look very nice. It's making good use of what appears to be ray traced global illumination and reflections. The cloth textures on the detective's cape look excellent. But if all of that comes at the cost of a playable frame rate, it's not worth the trade off – at least not on PC.

If TT Games' system requirements are accurate, most people will be better off playing this game on consoles where, for now, frame generation isn't a thing. Although the PlayStation 6 and Xbox Project Helix will apparently support the technology, so this won't be the last time we see developers trying to shoehorn frame generation into a game that doesn't run well in the first place. I hope I'm wrong.