The large levels from the PC were broken into smaller chunks with more frequent loading screens to manage memory.
To fit the massive PC game onto the Xbox's 64MB of RAM, the developers had to get creative. DOOM 3 [Xbox Classic]
Character models and environments were simplified, but high-resolution normal maps were used to keep the "bumpy," detailed look of the PC version. The large levels from the PC were broken
While the later BFG Edition and modern ports offered higher resolutions and 60 FPS, many purists still prefer the original Xbox port for its atmosphere. DOOM 3 [Xbox Classic]
The interface was overhauled to be more readable on CRT televisions of the era.