quote wikipedia:
"Chips are made with a variety of data bus sizes (most commonly 4, 8 or 16 bits), but chips are generally assembled into 168-pin DIMMs that read or write 64 (non-ECC) or 72 (ECC) bits at a time."
answer: 168
DDR SDRAM uses 184 pins.
Sdram has one notch. Depending upon the model of Sdram the number of pins it has can vary but a standard Sdram has 184 pins.
240
count them
The EDO RAM desktop memory modules have 72 pins and operate at 5V as standard
168 pins are used on SDRAM DIMM. 184 pins are used on DDR DIMM. There are either 30 pins or 72 pins used on SIMM. 184 pins are used on RIMM.
DIMM. Two types of DIMMs: a 168-pin SDRAM module (top) and a 184-pin DDR SDRAM module (bottom). Note that the SDRAM module has two notches (rectangular cuts or incisions) on the bottom edge, while the DDR1 SDRAM module has only one.
DDR runs twice as fast as regular SDRAM, has one notch, and uses 184 pins. Instead of processing data for each beat of the system clock, as regular SDRAM does, it processes data when the beat rises and again when it falls, doubling the data rate of memory
DDR SDRAM has one notch and uses 184 pins.
168
172
For server and high end stations nimber of pins are 240. For Laptop and Cube PC it is 214. (Refer Simmtester.com-Publications)