Freezing and disconnecting only when playing with Ryze

During gameplay I experience LONG 30 second or more freezes only when playing the Ryze champion. As wierd as that sounds, I never have experienced anything like this while playing even if the rounds are simultaneous. The freezes happen at the beginning and are followed by a massive response delay of any click for the next few minutes. For a while I will have relatively smooth gameplay and then I will have another freeze that will end in disconnecting. This is all very strange to me and I hope that someone can help....