DDR RAM compatibility question.

[adinu]

Im currently purchasing a computer that will have either ddr pc3200 or pc2700 ram. I also have an extra stick of ddr pc2100 ram that is not being used, so I wanted to know if i could use the 2100 ram stick with the 3200 or 2700 that will come with the computer. I have been told by a friend that they are all the same, but im not sure and want to know before i get the computer.

thanks

 

[ardy891]

yes u can use it but u wont b able to run at the speeds as the 3200, i fu mix ram then every stick will b downclocked to the same as the slowest ram!!

 

[zero4zero]

The computer you will purchase will have a motherboard bus frequency. You should always have memory that will match the bus frequency.
PC3200 have 400 Mhz frequency
PC2700 have 333 Mhz frequency
PC2100 have 266 Mhz frequency.
If you put a memory stick that has a memory frequency less than the motherboard frequency, then you are creating a bottleneck, which means that you motherboard bus will only go as fast as the slowest memory stick installed. In your case, you will be having more memory but your bus will be slower.
So make sure that before you buy the computer that if the bus is 400 Mhz (or 800 Mhz FSB [front side bus], it has 400 Mhz or PC3200 memory sticks. If not, tell the dealer that you will only buy if there are the right memory for the system.
Too often there are systems advertized with 400 Mhz bus and with PC2700 (333 Mhz) ; its' a shame.

 

[alvino]

It'll work, but the ram will run at the speed of the slowest stick, therefore hindering the performance of the other faster sticks.

 

[TRDCorolla1]

If you know the motherboard supports DDR400, it's better to get the fastest it can support (PC3200). That defeats the purpose of a computer upgrade if you go with something lower than a PC3200.

 

[alvino]

Or just keep it the way it is, and just upgrade the whole thing later on...