I vaguely remember explaining this via skype yesterday, but I'll repeat myself here for future searches. Table is not a good choice if you care about performance, because it has to calculate the dimensions of every single cell. A Grid should be used instead if the width of your cells is known ahead of time. Other than that, there isn't any difference between NGUI on iOS/Android and WP8. Only the UIInput script differs. Unity's performance on Windows phones though... that is likely still being worked on.