I never get drivers form the assembler; e.g. Asus or Gigabyte. I get them from the chipset manufacturer; e.g. Nvidia and AMD. Chipsets are typically unified unless hacked and that's not common.
I don't recommend overclocking unless the CPU is several years old and one wants to milk it or have special reasons like benchmarking. Otherwise the extra performance is not worth the trouble of reducing the CPU/GPU life or possibly risking the them plus the mobo. Even my 3.4Ghz to 4Ghz (even tried 4.4Ghz before) over clocked 8 year old CPU, and it was a high-end i5 at the time, is not making a difference now that many-multi core CPU's are out.