Anything odd with temperatures or power draws perhaps? nv-top shows both for me (but I run an AMD GPU + non-proprietary drivers), otherwise lm-sensors might be good.
nvtop seems to show normal usage
Neither the GPU nor CPU utilisation change at the 30 min mark? If one is pegged at 100% then it’s probably hard to work out what is going on. Running a singleplayer game staring at a wall and configured with limited framrate might let you run both the CPU and GPU at less than 100%, perhaps making it easier to see if one or the other suddenly changes.
As a general rule I hold suspicion to any marketing that claims that using CO2 (or other products of burning) is environmental friendly. The products you get from burning fuels are supposed to be useless and of low value, otherwise they are not burning them efficiently.
To turn CO2 into potassium carbonate (pearl ash) you will need a lot of energy. Where they get this energy from is far more important than where they got the CO2 from. I would not be surprised if it is more environmentally friendly to make the pearl ash through a different process and ignore the CO2 rather than trying to convert the CO2 into pearl ash.
Background chemistry
Fuels are chemicals with a lot of potential chemical energy stored in them. They are generally considered (at a minimum) flammable or “reactive” in some way.
When we burn fuels we turn them into products with very little potential chemical energy, mainly CO2. You cannot burn CO2 and get energy out of it, it is a “stable” or “unreactive” chemical. It has very little chemical energy stored in it compared to the original fuel.
The difference in stored chemical energy between the fuel (eg methane CH4) and the products (eg CO2) is turned into heat and then electricity (via steam turbines). If your products are still reactive then you have not used them to their full potential and you will not get as much heat out as you could (not to mention improperly burned products tend to be toxic, eg carbon monoxide).
Now let’s look at potassium carbonate (K2CO3). It’s a somewhat reactive chemical, it’s not anywhere as stable as CO2, you can observe this by the fact it readily wants to react with other chemicals (caveman test: put it on your skin and it will sting). CO2 is very stable and does not want to do much (caveman test: put it on your skin and you won’t feel it).
To make K2CO3 from CO2 you will require energy input. Turning an unreactive chemical into a reactive one is a bit like the reverse of burning something. This energy will probably come from burning more coal or gas. I suspect it will require more coal/gas than making the CO2 did, so net overall you will probably be releasing more CO2 than you capture and turn into K2CO3.
Of course if they’re using renewal energy (solar) for this step then this could be a net positive.
My level of trust in the honesty of product packaging and marketing is pretty low and if they don’t mention it then they obviously don’t think it’s important. 🤷
EDIT: I’ll also add that “carbon capture” projects (things that claim to get rid of or make use of the CO2 from burning fuels) are universally disasters or scams.
EDIT2: I’ve taking some simplification liberties with the chemistry here. Technically CO2 isn’t completely stable, you can do stuff like make weak acids in water with it, but I do not believe anyone has found a way for that to usefully use up what we emit from burning fuels.