PS5 Could Have Been Smaller If It Had 2 Smaller Fans, Says PS5 Engineer - News

Not to sound dismissive on you, as I do respect your technical knowledge, but he is talking about optimal approach, cost, control, etc. So just putting same RPM isn't really what they are going after.

I understand that part. Just saying that you can still connect both fans to the same fan controller to keep costs minimal.

Having them operate at the same RPM wouldn't be the end of the world either, my PC fans generally work in groups of 2 (5x groups in total for 10x fans.) and each of those groups operate at the same RPM. (I.E. Low speeds unless gaming.)

Where you want fan speeds to differ is if you are pushing or pulling volumes of air, but if you just have two small exhaust or two small intakes, then it's not an issue having them operate at the same rate.

Sony still made the right choice here from an engineering/cooling perspective, the "noisy" fans of old consoles really shouldn't be much of an issue this time around, Sony has learned and improved their design internally rather significantly.

Even their optical drives have noise dampening and vibration dampening technology, which is absolutely awesome, this is going to be a quiet machine.

The noisy fans was due to heat sink dust build up. If the heatskinks get dusty again the same thing will happen as before. I just hope the dust collectorts they put it stops the flow of dust to the heat sink.

Generally a larger fan spins at a lower RPM and generally has a larger surface area, so they tend to naturally be quieter and more reliable over the long term anyway... And do take longer to build up with dust.

On the PC what a GPU typically does is reverse their fan during startup for a couple of seconds to expel dust, not sure if Sony has done anything similar here, but would be awesome if they did.

But I do know Sony has included some "air channels" to allow you to suck/blow dust out with a vacuum/can of compressed air. Some smart design choices have been made that's for sure.

PS4's aluminum heatsink isn't exactly gigantic and it uses typical carbon based thermal paste, so it's heat dissipation isn't exactly the most efficient. PS4's noisy fans can be due to dust build up in some cases, but not always. PS4's small fan had to run at much higher RPM, which causes more vacuum, leading to higher dust intake depending on how dusty the general area is. PS5 has a massive copper and aluminum heatsink, plus liquid metal for thermal transfer, which will be highly efficient. PS5 also has a significantly larger fan all around, which will run at a much lower RPM due to it's size and the high heatsink transfer efficiency, leading to much lower dust intake, even in a dusty area.
As for the fact that two fans could have made it smaller but would have been more of a hassle. I can only assume it wouldn't have made the console that much smaller to make it worth it, on top of adding extra cost depending on how far they went with the dual fan design. By going with one single fan they save costs, helping with a reasonable launch price and possible subsidy to hit that price, while also leaving room for plenty of improvement on the eventual slim model down the road. PS2 and PS3 slim were seen as a much bigger improvement vs PS4 slim, especially in terms of the wow factor. PS4 already had the slim wow factor at launch, though it came with the noisy cooling downside. PS5 doesn't require that with SNY's present market position, though it does have it's own unique wow factor regardless.