Do you know what model AiO you have? Some models report pump speeds as higher since they have multiple magnets triggering the RPM sensor, so the 1600 might actually be 800 or even 400, which is way too low for the pump.
I would try setting the pump (and AiO fan) to 100% speed in the Bios for testing. Some pumps work well with a fan curve, some don’t.
Edit with more technical details: Normally each revolution should generate 2 Pulses on the rpm Feedback wire. But Pumps don’t always follow this spec so might over or underreport their actual rpm.
I picked up Starsector again this weekend and having a blast with a modded playthrough.