[Haskell-cafe] Data.Array.Storable vs GC

If you have a giant unboxed array that will never become garbage, it would be nice to put it somewhere where the GC won't bother with it. Since Data.Array.Storable arrays are allocated in the C heap, I thought it would be a good choice. However, I am getting very poor performance due to the GC copying 6G in each run. The only explanation that I can think of is that it is copying my giant array. Am I wrong in my understanding that Data.Array.Storable arrays should not be copied by the GC? BTW, I am using GHC 6.10.1 on linux. Thanks for reading.