Can somebody tell me what software developers for Mac use to monitor VRAM usage ?

It doesn't seem that OpenGL Driver that comes with the "Developer tools" is good enough for Apple.

From my reading on OpenGL Driver (reading free video memory) I have a memory leak on my computer.

Just using textedit is using vram ??? And it doesn't seem to be released after quitting the software.

My MacPro is at the shop and it seems that Apple doesn't recognize the same problems.

From my reading on OpenGL Driver (reading free video memory) I have a memory leak on my computer.
Just using textedit is using vram ??? And it doesn't seem to be released after quitting the software.
My MacPro is at the shop and it seems that Apple doesn't recognize the same problems.

vram-monitoring

"Instruments" is the answer to your question. It is part of the Xcode IDE. You're looking for the GPU driver and bottom right in the profiler there's a huge list which lists "Vram free bytes". Have fun!

VRAM monitoring