Your PC case’s clearance specs might be wrong. Here’s how to check

After Noctua tested “more than a hundred cases,” it found that 56 had a significant discrepancy between the actual CPU cooler clearance and the one listed by the case manufacturer. The most dramatic was a 10mm difference in Corsair’s popular 4000D and 5000D cases, which Noctua determined can handle 10mm more than listed on the spec sheet. (For those of us in backwards countries, that’s 0.39 inches—a pretty huge gap when it comes to computer components.)

The difference could be explained by a manufacturer adding in a dramatic margin of error to make sure customers aren’t scraping the sides of the case with their cooling hardware. But the more troubling finding is cases that show a larger figure for clearance than actually exists, which could result in wholly incompatible builds. In cases from Asus and Lian-Li, Noctua found real clearances that were 1.8mm and 3.5mm shorter than the specs listed by their manufacturers, respectively. That makes those cases incompatible with specific CPU coolers in Noctua’s catalog that should otherwise fit according to the manufacturer’s guidelines.

Again, I know we’re talking about tiny distances here, but millimeters can make the difference between a smooth afternoon of building and a week’s wait for a replacement part. To avoid this, Noctua has created and hosted a database of case specifications. Dimensions that vary from a manufacturer’s supplied data will be indicated with a question mark next to the “Max. cooler height” field. It’s another way that Noctua is winning fans (har har) among the PC building community.

After seeing nearly half of these values deviate from their official specs, I think I’ll start taking my own measurements whenever I need a new CPU cooler. Of course, that’s not possible if you’re starting a build from the ground up, which involves getting a new case and cooler at the same time. For that, a little research (and maybe a swing by Noctua’s new database) could help prevent some headaches.