Normal
Its what I've done. Installed a Sapphire 8GB RX580 (cos I'm doubling the build as a Hackintosh) - replaced the GPU fans with 2 x Noctua NF A12x25 configured as pulling from the card and exhausting out the bottom. These are connected to the card's single PWM fan power outlet and then split to each fan. Works great - thermals are a bit cooler than stock but noise levels, which was my main motivation, are night and day. EDIT - should also point out that these are the only fans at the bottom of the case. The only other fans are 2 of the same Noctua feeding a Celsius S24 AIO on the side. The build is so quiet I've done double takes about it powering on!