We study the effect of haptic feedback intensity on touch typing performance on a flat keyboard. In this study, we investigate how local and global haptic feedback intensities affect typing performance and examine if haptic feedback at a higher intensity brings more performance benefit. We also investigate if auditory feedback intensity affects typing performance. Participants are asked to type on a flat keyboard with given texts on a computer screen. We measure typing performance in terms of typing speed, efficiency and error rate at different intensity levels for both haptic and auditory feedback. The results show that the intensity of haptic feedback affects typing performance while the intensity of auditory feedback does not. Our findings suggest that haptic feedback is beneficial to typing performance and its intensity should be carefully chosen in designing a flat keyboard.