Memory Update for an old laptop

Question

I have an old HP Pavilion dv6 Series (model dv6-1140ej).

It has 2GB of RAM in 2 sticks. According to the specs, it supports 400Mhz DDR2 memory.

I would like to increase the amount of RAM I have.

Someone told me faster memory sticks (say 800Mhz) cannot be used when only 400Mhz are supported.

This is a bummer, because for some reason 4GB of 400Mhz DDR2 costs about 3-4 times more than a modern DDR2 stick with the same size.

Is this really the case ? Can't a memory stick work in a frequency lower than its optimal ?

Here is the CrucialScan results:

And now it's even weirder, with the help of "HP Support Assistant" here are the memory details:

1GB 7F7FFE0000000000 800MHz (X2)

Can I really use DDR3L-1600 SODIMM for this old laptop ?

Answer 1

The memory you need is PC2-6400 which is DDR2 at 400Mhz (almost the fastest DDR2). I'm surprised that Crucial offers a DDR3 option but your computer apparently doesn't support it.

Since there are only two slots and both are used, you will need to replace the ones you have to upgrade.

Note that 32 bit systems limit the available amount to 4GB (in case it applies to you).

To answer your question directly on faster memory being able to run slower, it depends on the actual fabrication of the stick but memory chips are very precise components and if you slow them down too much, they will lose their state before the next cycle. Modern RAM needs to be refreshed regularly (at the physical level).