is ddr2 ram backwards compatible with a ddr spec machine?

[Megatron]

Hello,

I have a ddr2-667 PC5300 ram stick.

Can I use that in a machine that uses ddr-266 PC2100 ram?

I thought I remember reading ram was backwards compatible but I just wanted to ask the experts.

Thanks!

 

[rogersmj]

No, they are definitely not backwards compatible. The notches are in different positions just to make sure you don't try it.

 

[Megatron]

Haha good point! The machine is a friend's machine so I hadn't even looked at what the notches look like.

So is it backwards compatible if it is the same number ddr#? I.e. ddr2 5300 and ddr2 2700?

 

[skuzzy]

Simple answer: no

*edit: It's a lot like trying to make a SATA hard drive work with an IDE interface.

 

[CanadaRAM]

Haha good point! The machine is a friend's machine so I hadn't even looked at what the notches look like.

So is it backwards compatible if it is the same number ddr? I.e. ddr2 5300 and ddr2 2700? You just can't switch between ddr1 and ddr2?

No such thing as DDR2-2700. The only similarity in numbers is PC3200 (DDR-400) and PC2-3200 (DDR2-400 which is rarely seen outside of servers)
Give it up - DDR and DDR2 are physically and electrically incompatible

sk: SATA / IDE isn't that great of an example, because you can get format convertors for drives, but not RAM.

 

[Megatron]

Give it up - DDR and DDR2 are physically and electrically incompatible

I think you mis-understood my second question, in part due to me getting some numbers wrong.

I didn't mean 2700 - the question I was asking in the second post was whether a faster DDR2 module would work in a slower DDR2 slot. I was just wondering about different speeds while both were ddr2. I guess I should have said ddr2 4200 and ddr2 5300.

Thank you for the info though I appreciate it.

 

[rogersmj]

I was asking in the second post was whether a faster DDR2 module would work in a slower DDR2 slot.

Yes, that will work.