My Intel Core i5-9400 is reaching around 95°C during stress tests with the stock cooler, so I'm considering an affordable four-heatpipe tower cooler such as the DeepCool AG400. The system uses an MSI H310M Pro-VD mATX motherboard, two standard-height RAM sticks, and a Xigmatek mid-tower case purchased around 2018. I don't know the exact case model, so I can't check its maximum CPU cooler height.
The cooler is roughly 150–152 mm tall, which seems reasonable for a standard mid-tower, but I'm worried about the side panel not closing. I'm also concerned that the cooler fan may overlap the RAM because the memory slots are close to the CPU socket. Raising the fan could provide RAM clearance, but might make the cooler too tall for the case.
Has anyone used a similar tower cooler with an mATX board and mid-tower case? Is a 150 mm cooler likely to fit, and would a compact 90 mm cooler be a worthwhile alternative?
3 Answers
A standard mid-tower will often support a cooler of this height, but don’t assume every case does. Also, the fan can usually be clipped a few millimeters higher to clear the nearest RAM stick. That does increase the total cooler height, so measure with the fan in its final position rather than relying only on the heatsink’s listed height.
The exact case model or its maximum CPU cooler height is the only reliable way to know. Check the manufacturer’s specifications if you can identify the case, or measure from the motherboard surface to the inside of the side panel. A cooler around 150–152 mm is relatively short for a tower cooler, so it will probably fit a normal mid-tower, but the available clearance can vary a lot between cases.
A parts compatibility checker can catch motherboard and memory conflicts, but it generally can’t confirm case clearance when the case model is unknown. If you can’t identify the case, a low-profile or 90 mm tower cooler is the safer physical choice. It may cool somewhat worse and run louder than a 120 mm tower, but either option should be a major improvement over the stock Intel cooler if mounted properly.
I may choose a 90 mm model because its adjustable fan should make the RAM clearance less stressful. I’m mainly unsure how much cooling performance I’d lose compared with a 120 mm tower.

I’ve checked the case but couldn’t find a model label. It came with the rest of the parts around 2018, so I may have to measure the internal space directly.