A CIPSI calculation was run once with the array storage, and once with the hash table storage. With the hash storage, the total wall clock time was increased only by a factor of two. To accelerate the access to the most frequently used integrals and reduce this overhead, we have implemented a so ware cache. All the integrals involving the 128 MOs closest to the Fermi level are copied in a dense array of 128 4 elements (2 GiB), and bene t from the fastest possible access.