I recently noticed a performance issue when playing LetterMiner on an iPad 3. When I tapped multiple letter tiles quickly, there was a delay before highlighting the tapped tiles. Why was there a delay?

I profiled the game on the iPad 3 using the Time Profiler instrument in Instruments, Apple’s developer tool for profiling iOS and Mac apps. When I ran LetterMiner in Instruments I didn’t notice any highlighting delay when tapping letter tiles.

No delay when profiling answered my question. The cause of the delay was my running a debug build on the iPad 3. Debug builds make debugging much easier at the cost of the app running slower. When I was profiling the game in Instruments, I was running a release build that runs much faster. It’s nice to know this performance issue has an easy solution. Run a release build.