Figuring out the airflow of the PS4 is like doing origami. The air comes in from the top of the back and goes out the bottom of the back. There is a aluminum-mobo-aluminum sandwich about a half inch thick in between.

The air come in through the top slots, over and through the bottom of the sandwich as the mobo is upside down. The air cools the sheet, cools the memory chips by little dimples on the sheet and then is sucked through the sandwich by many small holes in the sheet metal and then through the mobo- yes, there are airholes strategically placed on the the mobo! Look by the battery for most of them that are directly over the fan intake.

Now the air comes to the fan intake via those small holes and a couple of vents over the hard drive. The cutouts over the fan intake are particularly strange, square holes, small round holes, L shaped holes. From there it is out the fan across the top sheet, then the CPU/GPU heatsink, again with memory dimples, and out through the hot parts of the power supply.

Mylar connectors on the optical drive. No wonder they are failing. I HATE Mylar connectors, only good for intermittent contacts and coming loose in shipping.

Right is the the other poster and wrong am I! The heatsink not only has a cutout for it AND is held down by the two screws but it also has a bump out that makes better contact with the ALU. I am still trying to wrap my head around a screw that goes through a aluminum sheet, the motherboard, another aluminum sheet and into the heatsink is going to prevent the sheets from moving or bending. I would have to play with it to figure that out. Still, not a single chip gets blown on by the fan on the mobo as they are encased in that very thin sandwich.

SONY does away with ALL conventional ways of pulling heat from the console chips. The first is that the CPU/GPU is facing DOWN towards the bottom of the console. The next is that the heatsink is NOT touching the CPU/GPU chip directly and is also facing down in the case. The high speed graphics chips need to be cooled and it is done by dimpling the two sheet metal panels, 16 dimples in all. The ONLY means by which these SEVENTEEN contacts are made is by some sticky stuff on the graphics chips, thermal paste, and TWO SCREWS. Two screws mounted diagonally from each other and the holes can been seen in the mobo. Give this thermal sheet metal sandwich a good twist, squeeze, or bump and some of these 17 contacts are going to be bent, squeezed, or separated. Any non or poor contact will cause the board to measure overheating, stopping the console.

SONY took a big risk in trying to innovate here and it may be the cause of many of the consoles problems. That and Mylar connectors ( I hate Mylar connectors!)

Mylar connectors. I HATE Mylar connectors. They are flimsy, prone to popping out when shipping, and are great for making intermittent contacts. The are also hard to get in and out without destroying the wire, the socket, or both.

There is a danger here for little kids. The 120 volts for the power supply readily accessible to little fingers and probing metal tools like coins in the hands of children. The ends of the 120 volt wires are exposed, the fuse is exposed which will have 120 volts on BOTH ends, the capacitor is right there along with the power transistors, choke coils, and other things, including the transformers. Many will still be live even when the console is turned off.

Make sure to unplug the unit when there are small children around and the unit is sitting out in the open. When using it, put the back away from where little fingers can reach it.

I am so glad you did it so I didn't have to! Way too curious of what is inside!