Same problem here with Ubuntu 14.04 AMD64 on an Acer V3-571G with an Intel HD 4000 and an NVIDIA GT630M.
After VT-switching back and forth most of my screen stays black until its content gets updated. Flash videos don't update until I refresh the page. The flash thing also happens when just minimising the window. None of these things happen when I switch to the Intel chip.
Same problem here with Ubuntu 14.04 AMD64 on an Acer V3-571G with an Intel HD 4000 and an NVIDIA GT630M.
After VT-switching back and forth most of my screen stays black until its content gets updated. Flash videos don't update until I refresh the page. The flash thing also happens when just minimising the window. None of these things happen when I switch to the Intel chip.