As had been said, you will need a CPU cooler and with that case you'll be limited to a certain set of coolers that will fit in that case (the case web site shows which coolers they tested with). These coolers are more limited than larger air coolers so you will probably not be pushing any overclocking on that processor.
Also, I'm surprised you're not using the M.2 slots on the motherboard for SSDs as they are typically faster than SATA SSDs. Will you be compiling from SSD? Or only from the external drive? If so, you may be very much limited by USB-C interface to the external drive. Or did you choose the SATA SSDs for cost reasons?
What are the timing numbers on the 2666 memory? Most commonly the CAS or CL number will be listed, but you may also see a stream of numbers such as 14-14-14-30 (the first number in that stream is the CAS). This gives you some indicators about how fast this memory is relative to other products running at that clock. Lower numbers in the timing are better.
Did you consciously choose to only go with 2666 memory (for cost reasons) and not one that is XMP rated to 3200 or 3600? I would think your compile speed would be some combination of disk I/O speed, CPU speed (perhaps only single core speed matters) and memory speed. People should not forget about memory speed.
Do you really need 32GB?
(-1 AVX offset) on ASRock Z390 Taichi
with Noctua NH-D15 air cooler
CPU offset voltage of -25mv, runs VRVout 1.240-1.313V on full AVX load, 1.225-1.275V on non-AVX load
2x8GB [email protected] at 1.45V
, G.Skill F4-3733C17Q-32GTZKK (XMP rated [email protected]
EVGA GTX 1060 6GB OC with Corsair RMx 750W power supply
Samsung 970 EVO 500GB NVMe boot SSD and four other drives all in a Fractal Design R6 Case