Thinkpads Forum

I would like to know just how much more battery life I can expect from an x61s vs an x61.

Perhaps this is dependent on the specific processors, so let's say I have an x61 with a Core 2 Duo CPU T8100 @ 2.10 GHz (which i do) vs a x61s with a 1.8 GHz processor.

What is the ratio of the battery life of one vs the other? Will I see more than a 20% increase in battery life by switching to a x61s?

I have searched for this answer in many places. I know the x61s is more power efficient than the x61, but I do not know HOW MUCH more.

Thanks in advance.

tonnisw wrote:Will I see more than a 20% increase in battery life by switching to a x61s?

No -- not under normal use, and probably not otherwise either.

Here is why:
The Intel processors throttle down to almost "nothing" when they are not actually "computing", so unless you are running a torture test which keeps the CPU busy over 90% of the time, the relative differences in power consumption of the CPUs will not manifest themselves in the battery life. Under "normal" usage,the duty cycle of CPUs is probably in low teens or single digits-- let's say 15% -- and even if the differences between the CPUs were as high as 20%, 20% of 15% is not noticeable.

At most, if your "normal" use is, e.g., computing Fast Fourier Transforms or rendering in Photoshop, then you may see a small difference in the battery life.

Now THAT was a clear answer! Thank you very much.

i think the 61s processor was ultra low voltage?
might not be quite as straight forward as % of clock speed difference.
but even so, the cpu is only a fraction of the equation, lcd/drive taking up a gob of the load, so any difference will be not that big a deal. more important is how big the battery you are carrying unless u got some very high clock cpu.

here are sound round number charts
http://shop.lenovo.com/SEUILibrary/cont ... /Batteries
it also depends on its usage pattern.
if you are stressing a lower power cpu, it has less time to go into low power states, and so it will suffer.

tonnisw wrote:I would like to know just how much more battery life I can expect from an x61s vs an x61.

Perhaps this is dependent on the specific processors, so let's say I have an x61 with a Core 2 Duo CPU T8100 @ 2.10 GHz (which i do) vs a x61s with a 1.8 GHz processor.

What is the ratio of the battery life of one vs the other? Will I see more than a 20% increase in battery life by switching to a x61s?

I have searched for this answer in many places. I know the x61s is more power efficient than the x61, but I do not know HOW MUCH more.

Thanks in advance.

As Thinkpadder wrote, while using your laptop for common CPU non intensive tasks, there will be very small if any difference. When you throttle the CPU to higher load, some difference will occur due the higher power consumption of non-s CPU.

(my experiences from having both X60 and X60s)