Just to elaborate on this for completeness. There's broadly 2 types of behaviour.
1) Frame limited - This can be caused by an app having vsync on or a max fps set in games. This limit will change upwards with a faster refresh monitor typically. Windows tends to keep everything vsynced. Higher refresh means higher target FPS so more GPU load and higher temps (very slight)
2) Frame unlimited - The GPU always runs as fast as it can to generate new frames, it will run as fast as it can in both instances. You wont see temp differences.
GPU cooling is designed to handle the card at 100% load, so don't worry about it and enjoy your new monitor