Хм, а кто мешал почитать конкретный мануал

Модель этой платы Intel S5520SCR

Support for one or two Intel® Xeon® Processor 5500 series up to 130W Thermal Design Power
Support for one or two Intel® Xeon® Processor(s) 5600 series up to 130W Thermal Design Power
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3.2.1 Processor Population Rules
You must populate processors in sequential order. Therefore, you must populate processor
socket 1 (CPU 1) before processor socket 2 (CPU 2).
When only one processor is installed, it must be in the socket labeled CPU1, which is located
near the rear edge of the server board. When a single processor is installed, no terminator is
required in the second processor socket.