X200: Choosing RAM from the point of view of energy economy

[Nickolai]

Hi,

I'd like to upgrade RAM for my X200 from my current 2GB to 2x4GB. I wonder if I should choose memory modules with lower frequency, to save a bit on power consumption?

The price is practically the same and I believe perfomance impact of choosing one module over another would be insignificant, keeping in mind that higher-frequency modules have higher latencies.

I'm looking at these particular 4GB modules:
KVR1066D3S7/4G (PC3-8500, 1066 Mhz) (datasheet: 1.320 W max)
KVR1333D3S9/4G (PC3-10600, 1333 Mhz) (datasheet: 1.410 W max)
KVR16S11/4 (PC3-12800, 1600 Mhz) (datasheet: 2.580 W max)
Also, there's an option to buy some kit of 2x4GB.

I'm not even sure if the higher-clocked ones would even run properly on mys system. They should run at lower frequencies and latencies, but I'm less than fully sure if they will be recognized properly.

On the other hand, I don't especially like the idea of buying obsolete hardware when I can buy the latest one instead. So, if I could just buy the highest frequency modules and they will work at lower frequency and lower latency just fine, maybe I should go for it instead.

I guess this question generalizes to choosing laptop RAM in general, but I post it here in X2xx thread.

UPDATE: Now I looked at the datasheets and it looks like 1600 MHz can draw significantly more power than the other two, which are nearly identical. So, maybe I should choose at 1333 MHz?

[i2000s]

As far as I know, X200 can only use 1066MHz chips in your list. Higher frequency will be degraded. My RAM is coming soon...

[rkawakami]

Generally speaking, the faster the module, the more power it will consume at it's rated speed. In order to compare the different modules, you need to look at how much power they are spec'ed for when operated at the clock frequency of the computer system. The datasheets you provided do not have this information so it's impossible to determine. However, it's usually true that the newest memory designs will use less power than the older ones when operating at the same speed.

[mikemex]

A 1600 MHz module is likely to consume less power when running at 1066 MHz than a module rated for 1066 MHz only. This is mostly because, even when modules all look the same, faster modeules are usually manufactured using newer techniques or even manufacturing processes.

Go with the fastest module you can and pay attention to those who can run at those high speeds without a heat spreader. There is also low power DDR3 RAM but I'm not sure if the X200 supports it. It probably does.