I believe with the latest versions of the APIs, the fixed function pipeline stuff is now emulated in the programmable pipeline, but the two don't mesh well, so

I believe with the latest versions of the APIs, the fixed function pipeline stuff is now emulated in the programmable pipeline, but the two don't mesh well, so you end up with particularly bad performance. I've had to find and install the old DX9 runtime to get some older games to run at reasonable frame rate.