NVIDIA Optimus is broken

NVIDIA is known for its success and high-end graphics cards, but out of all their failures. Optimus is probably the worst.

What is Optimus?

NVIDIA Optimus is a solution for hybrid graphics on laptops, which allows both the integrated graphics of a CPU (or chipset) and a dedicated NVIDIA GPU to coexist in the same laptop, being switched dynamically. In theory, it should greatly increase the battery life of high-end laptops with dedicated graphics.
In reality, this solution is a steaming pile of garbage. Most of the time, the NVIDIA GPU is being piped through the onboard graphics, which means that performance is slightly reduced, which isn't a huge deal, but what is is that power management pretty much doesn't work at all, at least every time I had to deal with it.

For whatever reason, NVIDIA's drivers seem to be completely unable to turn off the dedicated GPU when it's not needed. On all of the three laptops I own with this feature; an XPS L511z, an XPS L702x, and a ThinkPad T520, the NVIDIA GPU is always at least somewhat enabled and drawing power. The L511z is especially bad for this, sitting idle at the desktop, the machine can draw 20 - 30 watts because its GeForce GT 525M is powered on for literally no reason. My ThinkPad T520 also has this problem, although it is a lot less of an issue for a reason I will mention later. The L702x also has this problem, although it's a lot less noticeable because the battery life is already pretty bad.

Linux?

Depending on the era of your hardware, Optimus on Linux will either somewhat work or not work at all, and on my machines... it didn't work at all.

Why not just turn it off?

On some machines, like my ThinkPad T520, you actually can pick between Intel HD graphics, the dedicated Quadro NVS 4200M, or both with Optimus. However, on a lot of machines, especially consumer ones, you just.. can't. Both my XPS laptops don't have any option for Optimus, the dedicated GPU can never be fully disabled except through software hacks.

Conclusion

Optimus is an annoying non-feature that I am glad to see go away, especially with the significant performance gains in AMD's onboard graphics, making low-end dedicated graphics irrelevant.