Even with this being meant as a joke, the conflation of two wildly different things here (sample size and findings from a sample size of hundreds of millions) is an apt illustration of why we're having this nonsensical argument in the first place. To be able to make that joke requires an ability to conflate radically different things and treat them as the same. And that's what this discussion is all about.
This just underscores that you don't seem to understand the concept of sample size. Either that or you're just doubling down after being called out on making a nonsensical comparison. Regardless of conditions, a sample size of one is never proof of a systemic problem. It can be, but you can never know that it is unless you increase the sample size.
Yes you do, because that extremely broad point isn't what you're arguing. You are specifically arguing that a 120mm AIO on a high powered GPU is inherently significantly more likely to fail than, well, any other cooler, be it air or water with a bigger radiator. But not only that, really: you claim was that this is such woefully underpowered cooling that "this is just asking for premature pump failure". That's pretty specific and strongly worded. And that was the claim made in your original post that I responded to. If you've changed your argument since then, we'll, then you need to make that clear.
It's likely not a coincidence, no, but are your two loops using the same pump? You weren't clear on that. Also, DDC(-style) pumps are notorious for poor longevity due to them not being directly cooled by the fluid (unlike D5s, which have metal-to-liquid contact and are built to be cooled by the passing fluid) and thus needing heatsinks and some airflow to keep cool. A DDC or similar pump without airflow, even with a heatsink, will die relatively quickly. I recently saw someone put thermal sensors on the PCB in a DDC with a decently good DDC heatsink (an EK one IIRC), and saw PCB temperatures in the 90s. Considering that, any increase in ambient temperatures, including adjacent but not directly coupled liquid temperatures, will push things towards failure. But the thing is, AIO pumps are much weaker than DDCs, and don't output even remotely as much heat. Most AIO pumps pull 5W or less in normal operation, DDCs range from 10-18W. Electric motors put are all roughly equally efficient, so heat output scales mostly linearly with wattage. Thus, assuming a similarly poor thermal design to a DDC, it will still take a lot more to cook a 5W pump than a 10W one. Btw, if you were using the Bitspower S1, did you add a heatsink? And were/are you and your friend running them at full speed? 'Cause that flat top they have on it looks woefully insufficient for cooling unless there's significant airflow across it. Oh, and for that comparison between you and your friend: were they in the same case? Did you have the same number of fans? Without that, they're not comparable. And tbh, even different fans means they aren't, as the low airflow from those slower fans causing less direct cooling of the pump might be just as much of a cause of the pump failing as the high fluid temperature. Most likely it's a combination of both - it was likely heat-induced failure, but pinning that to the fluid alone isn't supported even by your anecdotal data. A combination of hot fluid, a hot case, insufficient airflow across the pump, and insufficient pump heatsink surface area is a more likely explanation.
