MSI Afterburner has a version compatible with XP, you might be able to find it with a Google search. I have an older version running on my XP box. If you're using an NVIDIA card, NVIDIA had a tool called nTune that did this:
https://www.nvidia.com/en-us/drivers/ntune-5053800/
However, regarding "automatic detection", there wasn't really either the hardware or software infrastructure available to support this. Especially with video cards because the driver model in Windows XP didn't really allow for graceful crashing, so if something goes wrong, it's basically time to reset the computer. In addition, most GPUs until the early 2010s basically didn't have an idle mode or a fancy V-F curve system like we have now. So the GPUs weren't really designed anyway to have their clock speeds dynamically adjusted.