That's because people and tools look at the wrong values. $ free -m total used free shared buffers cached Mem

That's because people and tools look at the wrong values. $ free -m total used free shared buffers cached Mem: 2009 1491 518 0 466 363 -/+ buffers/cache: 661 1348 Swap: 1992 0 1992 Here, you want the number 1348, which is the "free" memory you have, not the number "518" which at first glance is the "free" memory.