Power Consumption vs Number of SO-DIMMs

This may be a silly question, but I'm about ready to purchase aftermarket RAM for my yet to be delivered W510. The device supports up to 4 SO-DIMM modules.

My question is: since each stick runs at 1.5v to 1.7v, what is the overall impact to battery life running 2 sticks versus 4? Obviously it equates to 3v to 3.4v vs 6v to 6.8v, but is that meaningful in any way? We talking something like 10 minutes difference in overall longevity?

 

Power consumed = Current (I) x Voltage (V).

each stick may run at 1.5 v but there is actually very little current that goes through it when you are not shifting large amount of data through them, the power usage differences should be extremely small.

 

I'd say on average they need 1-2 W per stick.

 

The DRAM frequency should also modulate along with the CPU, or at least that's how things worked with FSB. Not sure what the new memory management techniques are with the QPI bus.

Are you saying that the DIMM's won't consume more when the CPU reaches its maximum rated speed along with the RAM?

Not sure how they would consume more power than they are rated to consume.

 

And what brought you to that conclusion?

 

The data sheet of a 2GB So-DIMM DDR3 Micron stick.

 

I went ahead and bought a Mushkin 2x4GB kit. I might pair them up with the 4GB kit Lenovo will provide, if they play nicely together. I'll run some tests in 2 vs 4 sodimm configurations.

 

i think that would be the maximum power it can use. Just like TDP of CPU...

 

if the CPU reaches maximum speed, then it probably is also be shifting more data, which increases the current flow in the RAM modules.... so the power usage would also increase.

 

In your system, the difference in power consumption would be almost negligible. In say the X200, it would be noticeable.