Front intake dropped my coolant temps by 6°C over the top mount" is real, but the catch is that front mount usually means the radiator is eating the fresh air your GPU wants, and the top mount is eating hot air off your VRMs. So it's not really top vs front in a clean way, it's more about who gets the good air first. In a tiny Compaq box you can't have both, so the move is usually to keep the GPU on fresh intake and dump the rad up top, then just live with the noise since your card is the part that'll actually thermal throttle. That 70C GPU number isn't scary on its own, but it's the memory and hotspot temps that climb when intake gets choked, and those are the ones that bite you. If you really want the lower CPU temps, flip your rear fan to intake, feed the rad from the back and top, and let the front pull straight to the GPU.