I cannot imagine any difference in cooling because of horizontal position or tower. Air goes front to back in both cases. Unless we have side vents(on tower) or top intake(in tower mode again). but you will usually see that in gaming cases. All rack mount cases are designed for front-back airflow, and I cannot imagine how vertical position can affect cooling performance. Only if you won't screw down radiators on CPU, and they will fall off in vertical position
I also don't believe in problems with PSU or drives, because of position. There're servers that have drives vertical, drives horizontal and it works fine.
if you read my post carefully you will see that I specifically point out that I "DO NOT" expect problems with PSU or Drives as this parts do not care about how they are positioned.
however Cooling systems do.
here is why:
#1 many rack mount cases include special air shroud that directs the air flow across components. also most cases are designed with predictive air flow based on air and fluid dynamics laws.
it is simply expected that hot air will flow to the top where coll will stay on the bottom.
so case layout, and components positioning is done based on what is expected air flow behaviour is.
most rack mount systems do not expect air movement side to side but as you point out they do expect it front to back.
now, if a case is designed with say CPU to be more left positioned in respect to the case view from front because most of the drive cages are on the right and thus most of the hot air flows to the right.
if you put this case sideway on it's the right side than the hot air from the drives will rise up to where the CPU is positioned. let say you also have PSU on the right side of the case, than hot air from the PSU will rise up as well. so now you have an excess of hot air around CPU that is not handled properly since it is unexpected to be there. your CPU will overheat and kink out. maybe not right a way but eventually it will die from overheating. or you will get bombarded with overheating alarms. same with RAM
not saying you can not use the case differently but you have to be prepared for the consequences. at least plan on tackle them in time.
if you do decide to use the server in an unconventional way (in a way it was not designed to be used)
than you need to knew and maybe figure out what needs to be done to prevent issues.
like, putting an extra fans or more powerful fans in stead of stock.
maybe moving to liquid cooling for CPU and RAM if possible. encasing the server in a closed rack with extra cooling so the ambiance temp is low enough to counteract the improper positioning.
staf like that.
