Your submissions are judged on two clusters called Pyramid and Cube. It is up to problem setter (author of the problem) to choose which cluster should be used to judge submissions to the problem.
- Pyramid [deactivated] (Intel Pentium III 733 MHz) - consists of old solid Pentium III machines that serve SPOJ since its very beginning in 2004. Thanks to the fact that these machines are slow, judges created by SPOJ problem setters can more easily test the complexity of the algorithms used in your solution without creating enormous datasets (we can even tell the difference between O(n) and O(nlogn) if needed). On this cluster memory limit for submissions is 256 MB.
- Cube (Intel Xeon E3-1220 v5) - this new cluster consists of modern and fast Intel Xeon E3-1220 v5 CPUs. On Cube your submissions will run from 30 to 50 times faster than on Pyramid so you can expect that if you test your solution at home then it will have similar execution time on SPOJ. On this cluster memory limit for submissions is 1536 MB.