Yep, go 2MHz on HT up and once you're at or over 237HT ref, start small FFT priming for 15mins. If it passes, move on 2MHz more and then prime for 2mins, and keep going up and priming 2 mins until it doesn't even do 1min. Then you'll see where the chip limit for max MHz, benching and stabile operation is better. Once you get to an area where its failing below 1min, you know that you're max limit for screenshot/validation is very near. You can try after that for max MHz screenshot, max MHz valid, max benchable small apps (Pi), max benchable 3D or max 24/7 stability. It's your choice how you go about it, I did them all.
Otherwise it takes forever and just inaccurate guesses.