Performance of Guide.IsTrialMode on WP7
Trial mode is an important part of every XNA game. It gives the player a taste of the gameplay, and wets their appetite for what they can expect after purchasing the full license. It’s therefore important to understand how to best implement trial mode in your wp7 game.
One common issue we’re seeing is that games assume Guide.IsTrialMode will be fast. Fast enough to call every frame. Please don’t do this! While it is fast on your unlocked developer phone, you will be surprised by how expensive this call is when your game has an actual trial license. I think Klucher did a good job of explaining the issue, so I’ll just send you his way:
The short story is that you should not assume this call will be fast, and thus only call it at ‘load time’ in your game. Whatever that means depends on your game.