Mobile Core i7 920XM, Clarksfield: Nehalem on-the-go

Battery Life and Power

Wrapping up our tests, we have a couple battery life tests as well as results measuring power draw at the outlet. We used our standardized Internet battery life test as well as a best-case test of idle battery life.

If you only focus on battery life in minutes, Clarksfield looks like a poor solution. Battery life is similar to the much larger Eurocom M98NU and AVADirect D900F. The problem with the comparison is that the W87CU uses a much smaller battery. In our relative battery life chart, we calculated how many minutes of battery life you get relative to battery capacity. Looking at that metric, Clarksfield easily surpasses all of the other previous high-end laptop CPU solutions. The D900F and D901C both use desktop CPUs in a large notebook chassis, and they are at the bottom of the test results with the ASUS W90Vp not far behind. Eurocom ends up providing 33% more battery life per watt hour than the W90Vp, but the big winner is the W87CU, which is 50% better than the next closest competitor.

As a corollary to the battery life results, power results pretty much confirm what we see in the relative battery life chart. The Clevo W87CU with Clarksfield CPU uses a lot less power than the other systems. With the graphics card and other components drawing plenty of power, the laptop is by no means a long battery life solution, but with a larger battery and a less power hungry GPU it could certainly last several hours between charges.

What we really want/need is Arrandale, at least if you're after good performance without killing your battery life. i7-920XM has potential to draw very little power, but the maximum CPU load definitely reaches the 55W TDP, making it a poor fit for anything but large desktop replacement notebooks. Arrandale will bring us dual-core + Hyper-Threading on 32nm with maximum TDP of 25W and 35W depending on clock speeds (and probably 17W models as well). Another interesting possibility would be Clarksfield with lower Turbo states, potentially getting down to a 35W or lower TDP.