Sony PCV-R558DS - Manual (Page 66)

VAIO Digital Studio Reference Manual 52
Memory Module (DIMM) Connectors
Both sides of each Dual Inline Memory Module (DIMM) look very
similar. The side with pin 1 has a small "1" to the left of pin 1. Be sure to
orient a DIMM correctly in the DIMM connector (a small triangle on the
connector indicates pin 1).
OM04710A.VSD
D
IMM2
D
IMM1
1 1 1 1
Indicates pin 1
Memory module (DIMM)
OM04908B.VSD