DDR2 in DDR1 slot, same pin count

July 2, 2007 6:47 PM

Can I use 200-pin SO-DIMM DDR2 RAM in a 200-pin SO-DIMM DDR1 RAM slot?

I've done some googling about this, but the only answers I've found are that DDR2 has 240 pins and DDR1 has 184 pins, so it wouldn't physically fit. However, my laptop takes 200-pin SO-DIMM DDR ram, and I couldn't help but notice on Newegg that 1GB of 200-pin SO-DIMM DDR2 ram goes for less than half the price of the same amount of DDR1 ram. Can I buy two sticks of DDR2 ram and save myself a hundred bucks, or do I have to stick with the DDR1?

posted by pravit to computers & internet (9 comments total)

Pretty sure it's backwards compatible, yes.
posted by East Manitoba Regional Junior Kabaddi Champion '94 at 7:13 PM on July 2, 2007

From what I can remember, the notches on DDR and DDR2 SODIMMs aren't the same, even though they both have 200 pins, so it wouldn't physically fit.
posted by wsp at 7:15 PM on July 2, 2007

Err, no, DDR2 is an entirely different specification. It is NOT backwards compatiible. Expect to lose a lot of magic smoke and possibly a laptop.
posted by damn dirty ape at 7:20 PM on July 2, 2007

The two run on different power supply voltages. If you did manage to get a DDR2 ram into your DDR slot (and I'd be very surprised to find that they're keyed in a way that makes this physically possible) then your laptop's 2.5V DDR RAM power supply would toast your 1.8V DDR2 RAM.
posted by flabdablet at 7:24 PM on July 2, 2007

Yeah, they're right. There's a physical difference, it won't fit.
posted by East Manitoba Regional Junior Kabaddi Champion '94 at 7:26 PM on July 2, 2007

****NO**** it is NOT possible. It wont fit.
posted by SirStan at 8:20 PM on July 2, 2007

Look, just go ahead and try it, AS LONG AS YOU'RE NOT FORCING ANYTHING.

Odds are even if it doesn't work (which it won't), you won't fry anything. And then you'll know. Won't that be nice?
posted by SlyBevel at 8:45 PM on July 2, 2007

"Go ahead and try it" means trying to put the round peg in the square hole, the module will physically not insert into the socket.
posted by Rhomboid at 9:04 PM on July 2, 2007

Understood. Guess I have to shell out for the DDR1 memory, then... Thanks for the answers!
posted by pravit at 9:38 PM on July 2, 2007