I bought one with crucial 8gb ram.
I bought it for vmware but:
ML115G with ESXi - SATA recognised for VMFS but poor performance
ML115G with ESX - SATA recognised after hack and great performance, but causes SCSI errors and eventually hangs ...
SO mine is a door stopper at the moment.
I've had no problems or performace issues running both ESX 3.5 and ESXi you must have set something wrong mate