The recent builds of Construct are optimised to use the lowest amount of VRAM possible - if you start adding effects it starts needing more VRAM, and if that VRAM isn't available, you're stuck and you simply need better hardware.
Developing games in the IDE has higher requirements than just playing them at runtime. It's more likely you'll be able to play the finished exported game on a 32mb card, but for development, you need a better machine. I'd go for a 128mb card to be on the safe side.