Set frame rate for OpenGL render?

I’m trying out an old ATI graphics card, an HD5450, in order to get away from some high DPCs from Nvidia drivers/cards.
LatencyMon reads great now…
However, it’s not the most powerful card by a long chalk.
In 1080p with OpenGL rendering it’s taking +60% of my GPU load.
If I’m not playing and there’re no level meters running it drops to 0% load.
In contrast, Vital, which is a very visual plugin, takes less that 40% of the gpu even on a busy patch.
I think Vital uses DirectX so perhaps it’s something to do with the old AMD Win10 OpenGL drivers.

Anyways…
Is there any way I could limit the refresh rate of the OpenGL gui?

Thanks,
Neil