Warning: I put a full ATX board in an old 1998 Dell tower and it beat my $180 modern case
I had a Ryzen 7 5800X3D and a 3070 Ti sitting in a $180 mesh case with 6 fans and my temps were fine but loud. Then I found a 1998 Dell Dimension XPS tower at a garage sale in Tacoma for $15 and jammed everything inside. I had to cut the drive cages with a $20 rotary tool and add one 92mm fan in the front, but the solid steel panels killed all the noise. Under load my CPU dropped from 78C to 72C and the GPU went from 74C to 69C, mostly because the old case has way more open space inside than my fancy one. The whole thing looks like a beige brick from 1999 and nobody at my LAN party believes there is a 5800X3D in there until they see the benchmark numbers. Has anyone else tried a 90s Dell or Gateway tower for a sleeper build, and did you have to mod the front panel for airflow or just leave it stock?