Latitude E6400 Owner's Lounge

I barely managed 10-10.5w on idle with wifi off... Backlit keyboard certainly does not help. 10% or so less battery life if on all the time.

As for undervolting, there is no risk, just takes a good chunk of your day (did for me today anyway). You should do it, so I can compare numbers with you . We have similar specs.

Vista power saver was kind of weird for me though, so I'm not going to try that again.

As for the difference in RPM, could be plausible, but some people say they experience both and they have almost no difference.

 

Ok. I read flipfire's undervolting guide and it looks encouraging. I'll read it a few more time just to make sure I know what I'm doing

 

first, make sure it is completely plugged in. The centre pin in the plug carries the PSU details. If it is fully plugged in, you will get that message if it is a 65W PSU and nVidia GPU. There used to be that message also with the Intel GPU but that got fixed in BIOS A09 onwards.

Flash on web pages can use a lot of power, even when not connected to the internet. I use Firefox + FlashBlock.

If it is any comfort, I am also in the 10W to 11W range at the moment, even with the brightness 1 notch above minimum. I have the keyboard backlight just below half brightness. However, I do have a lot of applications running so the %C3 (another perform counter) is around 90%. (%C3 is an indication of CPU sleep time.)

I know from experience that if I get offline and I'm just doing something like word processing then I can get down to around 8W.

John

 

There is no risk in undervolting.If you bsod, boot in safe mode.

 

My quick procedure for setting up the undervolting is to (i) stress the CPU using 2 x Prime95 or similar; drop the maximum voltage in RMClock by one step every 10 seconds or so until the computer BSODs or Prime95 reports and error; then set RMClock's maximum voltage to 2 steps above the failure voltage and run an overnight test using Prime95 or similar. Then, for extra safety, set the voltage one step higher. I also use the auto-interpolate function. Finding the optimum voltage for each intermediate speed isn't worth the effort IMO since the CPU spends most of its time either on idle or full speed.

John

 

Ok, I may be completely wrong here so please correct me. Undervolting won't help my battery life at all when I switch to Vista power saver mode since undervolting only changes the highest multiplier and not the lowest. I've noticed that on power saver mode, my P8600 never goes over 800Mhz so the CPU won't even get to the point where undervolting would matter.

 

It will help your power management. The equation for power(measured in watts) is P=IV where I is the current and V is the voltage. If you lower the voltage, you directly lower the power.

 

Yeah, but what he's saying is that on power saver, his CPU is on the lowest multiplier, which cannot be undervolted because the default is already at the lowest in RMClock.

 

How do you get that anyways? CPU-Z always shows 1600mhz at 1.0X volts even with lowest power saver settings for me.

 

Get what?

CPU-Z shows for me my core speed around 1.6GHz and voltage at 1.038V.

If you use SuperLFM, it drops it even lower by cutting FSB in half. I'm running at 0.80GHz according to RMClock.

Edit:

On another note, I keep getting the message that a storage device was connected. It is annoying and I didn't connect anything so...