You should be fine. 58C is a pretty low temperature and as far as memory goes 1750MHz is going to be the true frequency and not the effective frequency. VRAM is a quad data rate technology meaning there are 4 bits stored or sent for every clock pulse. So it acts like it is running 4x the clock speed then it actually is. So 1750MHz x 4 is 7000MHz effective clock. Similar stuff for DDRX ram which is double data rate so a DDR4 kit at 3600MHz is actually running at 1800MHz.
I doubt you will have any issues at 7800MHz (1950MHz true) effective clock