When the slider or button is yellow/gold like that it's not actually applied yet. It's not changing anything on the computer. You need to click the Apply button on the settings page in the upper right quadrant.
I double check my settings are working by running the built in stress test (or prime95) and seeing the graphs change at the bottom. I've had it where BIOS settings seemed to prevent XTU from working properly. That increasing my turbo ratio didn't allow my CPU to run faster.
I have a pretty old computer though (i7-4790k + z97 chipset), so maybe that isn't a common experience. It's so old I can't use the latest XTU version! 7.x... I'm still on 6.5.2.40 which I'm unhappy was harder to find that it should be (Intel didn't have a copy to download anymore).
Above that Apply, and it's partner Discard, button XTU can show 4 different sets of values (and a percentage change column too, where you pick which 2 columns...I chose default vs current to see my change versus Intel specs). I can't remember the default 2 columns it shows until you change a setting, but I made mine show all 4 possible. Just so I would be very clear about what was happening. Default (Intel specification) vs boot time (what BIOS told it to do) vs proposed (a setting changed in XTU, but isn't live yet) vs current (if you ran something, these settings are what the hardware should follow).
You can change settings for a lot of the display areas of the program by clicking the very small wrench in the upper right corner of the control (each area can have it's own little tool). I like dark mode, and the blue color of the wrench can seem almost invisible.
There are lots of values you can show in the graph area in bottom left corner, and the current value entries in the lower right. Though they're not all equally useful. And with the graph it can become hard to read with them all on. I often hovered my mouse to make it show that time point off to the graph's left.
