Dell T3600 can't boot - don't know cause by Memory or CPU

Hi All,

I purchase Dell T3600 from ebay. It comes with 8GB of RAM. I want upgrade to 32GB but face problem need your help.

Here is the condition:

1. Everything is good and pass pre-boot diagnostics when used 8GB (4GB x 4) RAM.

2. When I insert new RAM modules (8G x4, Kingstom), the PC stops at pre-bios status and LED indicator shows "3" and it stops. The screen is black. LED indicator on case shows "3".

I try RAM modules (8GB x4) specific for T3600 from two different 3th party suppliers, but all stops at pre-bios status and with same error LED number "3". I check service guide what LED indicator "3" means, it said CPU error. But CPU already pass pre-boot dianostics so I don't know is it CPU error or RAM or even motherboard error.

Anyone had same problems or any suggestions? Thanks.

My T3600:

CPU: E5-1650

RAM: 8GB (2GB x4) ECC Registered

OS: Not install yet.

Video card: nVidia Quadro K2200