Fast video memory access must be enabled in dgVoodoo for better performance with lens flares. It does something weird so it's a bit problematic in general. Lag spikes are still noticeable at very high resolutions, eg. 4K. It also depends on CPU speed, with slower CPUs one may experience the issue at lower resolutions. Running an older version of the game will also make it crash randomly due to a bug that makes it cross the buffer boundary.
My patch comes with its own frame limiter. If you have Windows 10, you can just press Win + Alt + PrtScrn to make a screenshot. Years ago, I used DxTory for that.
"When a human being takes his life in depression, this is a natural death of spiritual causes. The modern barbarity of 'saving' the suicidal is based on a hair-raising misapprehension of the nature of existence." - Peter Wessel Zapffe