Is this a new integration? If yes, do have a Non-V2 processor available?
If you have a Non-V2 processor, boot the server with one processor and 2 memory modules(A1, B1), check if its restarting. If not, update the firmware to the latest and then connect a V2 processor.
I would also recommend you to try clearing the CMOS using the jumper. refer http://download.intel.com/support/motherboards/server/sb/g24881004_s2600gzgl_tps_r1_1.pdf. Refer page: 5 for jumper location and 96 for procedure.
I see. This seems to be an issue with the board and may need a replacement. One of the troubleshooting is to check without the memory modules connected. Power on the system without the memory modules and check if the system still reboots.It should give you 3 beeps without memory and the system should keep running without display. If it still reboots, try changing the power supply to a 700/750 watt[if available] to isolate the issue. If unavailable or if the issue persists, you should contact Intel customer support for replacement with the serial number of the product.Intel customer support: http://www.intel.com/p/en_US/support/contactsupport