How many fans in I Mac 2021?

The upper model has a Larger Storage Drive, Ethernet connection and 2 USB 3 ports.

see > https://www.apple.com/shop/buy-mac/imac

The lower model has a 7-core GPU and the upper models have an 8-core GPU. Posting hardware tare down and repair links will get removed, but yes it looks like the lower model has 1 and both the mid and upper models have 2.

I’ve been a non-professional computer user since the 1980s and the thing if learnt about choosing a computer specifications is to first define what you want out of it. Once you have specified your uses then it’s a matter of matching this to the hardware specifications.

I recently changed from an older dual quad core Mac Pro with 16MB of memory and three internal hard drives each of 2TB to a base model M1 iMac with 8GB memory and 512 GB SSD. My reason for the apparent downgrade is that I don’t do heavy duty photo manipulation, I do no video work and never play games. From my pre-research the base model on chip graphic capability is only about 5% less than the next model with one extra core and that the M1 memory management is different to previous machines meaning that 8GB is satisfactory for most day to day operations. However in financial terms buy as much memory & storage as your pocket can handle as there is no after market upgrade.

I think the extra fan is not for the M1, but the (configurable) larger SSD hard drive and extra electronics for the ports. I am not sure why you are concerned.