I want to make a game that can run well on old computers from around 2010 but I don’t know what I need to do with the game to have it not need a lot of dedicated video ram and not need a quad-core processor and not need much system ram.
How can I make a game that doesn't demand much from the player's system?
I think you’ll find that pretty much impossible with UE, because the engine itself requires a pretty recent computer to run. Even if your game has nothing in it, the engine still has to run, and that requires recent hardware and system components.
You need to look into a lot of optimization, reducing draw calls, simple meshes, how to optimize your materials and reduce their instruction count, how to adjust engine settings and disable features to increase performance, reduce texture sizes, how to pack your textures to use less memory, get away from doing things in Tick, research what features use the most resources and or processing. maybe even look into using making or using a custom shader to simplify the rendering. I can’t tell you specific settings or features, but I can tell you it might take a good bit to find the information your looking for to reduce the engine to somthing as simple as possible. Although, 10 years ago would be doable I think, but the first thing I would look into is the lowest directX requirements for UE4 to run and if systems that old would support that version of DirectX.
To add to what blindminds said: you mostly wanna focus on reducing the shader complexity for whatever scene your working on. If you have a large open world environment, really try to reduce the amount of transparent textures, opting for masked or opaque alternatives (tree leaves, etc). I’ve found that the number of triangles in the scene doesn’t matter too much but you can still gain a lot of performance by tweaking the LOD values of environment objects.
Also consider alternative art styles that may still appear aesthetically pleasing but that uses low res textures and models:
Yes, I double up on that comment about reducing complexity shader and transparency I have found to be a major shader to avoid for this. Unlit, Opaque would be the best.
What kind of game are you intending to create? Why not simply use an earlier engine version from UE3?