Hold on,
Let me turn off my Hepa Air Purifier.
No, I don't really hear anything loud.
Just a low, low hum from all the combined fan in my Antec Sx1030.
Either that or I have gone deft from the Air Purifier.
If anything the Quantum Lm Hd is louder, but now I have a new IBM deskstar.
Notice, my Antec Sx1030 has alot of opening where sound can be leak out also. So if it's low on mine, it will probably be lower in yours.