CPU SpeedStep/TurboBoost doens't function right with AC ONLY

[hamburger]

Have you ever tried to use your T410 with AC ONLY (no battery)? The SpeedStep/Turbo Boost doesn't work right for me. It always works with 9 multipliers (1.2MHz).

My CPU is i7 620M, BIOS version 1.09. The multipliers are tested with CPU-z and Argus Monitor.

I enabled the SpeedStep and set Maximum Performance in the BIOS, and I use Maximum CPU in Power Manager. However, it always works with 9 multipliers even though I used prime95 to give it workload.

The SpeedStep/Turbo boost working status doesn't make any sense to me. I tried to uninstall Thinkpad Power Maneger, but still no lucky.

If I disable the SpeedStep/Turbo boost, its maximum multiplier value will be 20.

I doubt the T410 BIOS may have bugs.


Please help. Thanks.!

[Harryc]

I would say that this is normal behavior without a battery. I've seen this on a number of machines over the years, and the only reasonable explanation I've seen is;

When operating at highest CPU speed and with high current usage peripherals attached (CardBus cards, USB devices, etc.), the required operating current may momentarily exceed the capability of the AC Adapter. When the battery is installed, the battery can supplement the power during the momentary peaks.

When the battery is removed from the ThinkPad computer, it switches to "Battery Optimized" speed (lower speed) to reduce peak power demands and to prevent the possibility of input voltage dropping too low, causing the ThinkPad computer to power off.

Source - http://www.thinkpads.com/forum/viewtopi ... 22&start=0

[hamburger]

Thanks for your reply.

That is a reasonable explanation. I suspect that too.

[hamburger]

This official explanation seems more like an excuse for me. What I think about it is a flaw in its design. It is ridiculous that the problem has been there for at least 6 years!

My reasoning is very sample. If using AC only cannot give the laptop enough power at "momentary peaks", how could desktops work with just AC? If this is an inevitable design choice, why not every laptop has this problem?

It is a shame for thinkpad having this problem unfixed for more than 6 years!

[Colonel O'Neill]

Desktop PSUs supply a lot more power (I have a 300W in a creaky old P3) than do laptop AC adapters.

Perhaps fiddling with some of the Power Manager settings will work? I use RMClock to lock the multiplier into highest clock on my P8700 when necessary, but RMClock doesn't support the new i-Family of processors, does it?