jroymd

Whenever I see pictures and videos of AIO cooling systems I never see a discussion about radiator orientation. Almost all systems displayed on websites and advertisements seem to have the intake and output tubes at the top of the radiator, usually for mounting convenience, I assume. The problem is that all sealed AIO systems contain a small amount of air with the cooling fluid. Since air naturally floats to the top of the fluid (and therefore the radiator) the CPU pump end up pumping mostly fluid but also a lot of bubbles, which is referred to as cavitation (see The Hunt for Red October), which decreases the pump efficiency and probably shortens the life of the pump. These AIO pump systems are analogous to gasoline powered automotive engine cooling systems where typically there is an intake hose at the top of the radiator and a lower hose receiving hotter coolant from the engine. The main difference here is that cars have a reservoir system that not only receives excess coolant from thermal expansion, but also vents residual air at the top of the radiator and only aspirates coolant back into the radiator. So my obvious question is why aren't all AIO systems designed with the intention of mounting the tubes to be placed at the bottom of the radiator?

I have a similar problem with my new system. I have an ASUS STRIX X299-E Gaming II motherboard, Intel Core i9-9900-X CPU, Corsair H110i RBG Platinum SE. Upon booting the BIOS initiation stops with the error comment stating that the CPU fan is not operational. Also, the CPU temp quickly ramps up to over 90 degrees Centigrade (before I turn it off). The single wire three-pin "tach" plug is attached to the CPU_header, although I have tried the CPU_Opt header and the AIO pump header. SATA connector is attached properly, and the fans are connected to the harness. With this setup I cannot get past the intial CMOS BIOS boot sequence. I have not been able to turn off the lower CPU fan threshold because the CPU temp rises so quickly and I don't know if the CPU temp is true or a false temperature. I really don't think it is a mounting problem and I have use older Corsair AIO liquid cooling systems without the tach wire. Interestingly, in trying to resolve the problem, I replaced the H110i with a simple Thermaltake CPU heatsink/fan cooler and the system boots up and the CPU temperature runs between 30 to 50 degrees Centigrade, depending upon CPU usage. I would prefer to use the H110i RBG, but I am not getting anywhere. I am reluctant let the system run too long at this high CPU temp since the CPU is quite expensive to replace.