Niresh 10.8 Mountain Lion and updated it to 10.8.2 with developer account, but after update some of apps won't open. It's better to stick with 10.8.1 for now. Mountain Lion memory management is much better than Lion has, but I will downgrade to Lion again, due to some problems I am experiencing here. 

Hardware:

GPU: Intel Pentium E2140 @1.60 GHz
GPU: Gigabyte Nvidia GeForce GT 430 OC
MBO: ECS 945GCT-M2/1333 (v1.0a)
RAM: 1 GB DDR2