In this paper, we conducted two different studies. Our first study deals with measuring the flickering in HMDs using a selfdeveloped measurement tool. Therefore, we investigated several combinations of software 360° video players and framerates. We found out that only 90 fps content is leading to a ideal and smooth playout without stuttering or black frame insertion. In addition, it should be avoided to playout 360° content at lower framerates, especially 25 and 50 fps. In our second study we investigated the influence of higher framerates of various 360° videos on the perceived quality. Doing so, we conducted a subjective test using 12 expert viewers. The participants watched 30 fps native as well as interpolated 90 fps 360° content, whether we also rendered two contents published along with the paper. We found out that 90 fps is significantly improving the perceived quality. Additionally, we compared the performance of three motion interpolation algorithms. From the results it is visible that motion interpolation can be used in post production to improve the perceived quality.