Jumpexx

Planning my first new build in a while and I keep going back and forth on cooling. Case is a Fractal Pop Air Mini, board is the ASRock B650M PG Riptide, CPU is a 7800X3D, and GPU is a 4070 Ti Super MSI Ventus 3X, about 322mm. I want to stay on air.

Current list has a Peerless Assassin 120 SE. In that case the cooler sits pretty close to the rear 120mm fan. I've seen a few pics where people run the rear fan as intake on dual-tower coolers to feed fresh air straight into the fins, but the Pop Air Mini already has decent front flow. Is a rear intake actually worth it, or is that only for cases with bad front mesh?

Also eyeballing the NH-U12A instead if I can find a used one cheap, mostly for RAM clearance. Anyone running a dual tower in this case with a long GPU?

Hey, first post here. I was literally looking at this same case for my first build today. I thought the rear fan always had to be exhaust? My friend told me rear intake would blow hot air back over the VRM and the GPU, but maybe I misunderstood. Are you using the stock fans or replacing them? I haven't bought anything yet but your GPU length note scares me, I didn't consider that might hit the front fans. Does the drive cage matter too? Sorry if that's a dumb question.

@BuildNoobTess rear intake isn't always wrong, but it only makes sense if you flip the front top fan or run top exhaust to balance it. On the Pop Air Mini I'd keep it simple: rear exhaust, front intakes, maybe one top exhaust above the CPU if you have a spare fan. For the PA120, the rear fan isn't fighting the cooler as much as people think; it's actually pulling through the fin stack.

@SataSal I'd skip the U12A unless you care about noise or need every mm of RAM clearance. The Peerless Assassin handles a 7800X3D all day. That Ventus at 322mm is long, but the Pop Air Mini clears around 365mm without front fans. With a 25mm front fan you're still around 340mm, so tight but fine.

If you go rear intake, test both orientations before you commit to cable management. Most people lose a couple degrees on the CPU and gain it back on the M.2/VRM.

Agree with cheap_frame on testing both. I ran rear intake on an NR200 and it was great for CPU temps but dumped warm air onto the back of the GPU in that sandwich layout. In a normal mATX tower like the Pop Air Mini, the rear is already close to the CPU tower intake, so flipping it can help only if you remove nearby PCIe covers or your top fan is strong enough to pull the warm air out before it pools.

One thing nobody asked: what board? If it's the B650M PG Riptide, the CPU socket sits a bit higher than some other boards. That makes the top fan more useful and the rear fan less useful. I'd do two 140mm front intakes, one 120mm rear exhaust, and leave the top closed or one 120mm over the VRM. Cable-wise, route the 8-pin before the top fan.