FWIW AquaComputer changed the block design after they shipped me the sample so my AC results may not be worth staking a lot of money on. However the XSPC and Koolance blocks I repeated a bunch of times and they were repeatable. AFAIK none of the other testers were running as high power levels as I was, nor did anyone else test vs a large range of flow rates. As for fin structure when I did the massive CPU block roundup, I tried to correlate fin structure, # of channels, channel width, total surface area to actual thermal performance and couldn't. Yes I was surprised that the XSPC did so well with that structure and of course at some point a lack of surface area will limit a block but it could be possible that other factors are limiting performance too. In reality the block to block variation was tight which makes sense to me given how many years of block iteration we've had now. It would be surprising to me if a manufacturer released a terrible block. The main difference between blocks for me was the VRM temps and that separated out which blocks not to buy more than the core temperature IMO.
What can I say when Bundy doesn't correlate with my results? Some people will think either one of us is faking it, but the reality is that we have slightly different setups: - different gpu samples, different motherboards/cpus, different batches of TIM, different screw torque for mounting, different batches of thermal pads, different probes, different loading power, different block samples. In testing little things can make a difference. I'd love to correlate every time with every other reviewer, but sometime that doesn't happen and my first priority is just trying to do the best testing that I possibly can
I try and test things for the 24/7 overclocker that wants to optimize everything and push as hard as they can without killing things. That's how I run my systems, and so that's how I like to test things
It's worth pointing out that most manufacturers design their block to be the best and a lot of them test it against others blocks and some get upset when I don't correlate with their testing. Of course it's impossible to correlate with everyone's testing when they all think their block is best. I'm sure Bundy has seen/heard the same thing.