Processor performance with C-DOCK II - XP Pro

Question

Hi,

I've got a C640 P4 1.8ghz,512Mo, XP PRO SP2.
I've spotted lately a funny thing and I would like to know what's going on :

Laptop + AC power + DOCK II = 1.2 Ghz

Laptop + AC power = 1.8 Ghz

Intel Freq. utility always displays Expected Speed 1.8Ghz, but the Read result is different if I am docked or not.

I've checked the powermanagement setting, the hardware profiles.
it seems that the processor is throttling down coef x18 while undocked and coef. x14 while docked, bus and Ram speed are correct.

I am wondering if it's not a bios feature implemented by Dell to prevent the laptop of overheating while docked..

any help would be appreciated.

Thanks.

jer13 · Answer

any bright ideas on this one ? ;) J.

JersWork · Answer

Not really.  I have a C-Dock II and use it with both a C800 and a C840 (both running XP Pro).  Neither of them have the problem you are describing,  but I did realize that I also run SpeedSwitchXP (from the I8KFanGUI author).   It is possible that your XP power management registry settings have gotten corrupted.  This was discussed in the past.   Wait,  here is another side thought.  Do you have a PA-9 adapter on your Docking Station?  If you only have a PA-6 adapter,  then your system might not be gettgin enough power to run at full speed,  and therefore only runs at lower speeds.

ferret1964 · Answer

I have a similar settup a C800 & a C840.

The power adapter used by the CDock II is the PA-6, the 70W Adpater which will work with both the C800 & the C840. The C840 will drop to low speed when used with the 70W adapter. A 90W Adapter does work with the CDock (I & II), but I'm not sure what the effect would be on the C800. As far as I can tell using a 90W Adapter with the C800 is most likey a BAD idea. Does anyone have any experience with this?

jer13 · Answer

Hi guys,

thanks for the input. I've double checked the power setting, I've even done a clean XP Pro install on a new Partition, no luck...still stuck at 1.2Ghz instead of 1.8Ghz

For the power supply, I've a PA-6, but I can not find this 'grey bottom' adapter that came with my laptop (probalby left somewhere), all this other adapters I have are PA-6, therefore I can not test with a 70W or 90W PSU, but this would be something to investigate.

J.

jer13 · Answer

Ok,

I've done my homework, I re-enabled the option "message at boot while docked blabla...." and of course I do get a lovely message saying :

the 70W adapter will not provide enough power, so the processor speed will be lowered to... blalbla... you must use a 90w adapter call dell to buy one... Well, we found what was the cause.

but I can not recall if I had this 90W power supply when I bought my C640, I had many dell latitude C-series, I remember seeing this grey bottom one, but I definitely not have this 90W with me :-( I've got 4 of them, but all are 70W.

Anyway thanks for the input
J.

JersWork · Answer

Actually, Dell will sell you the PA-9 adapter for the C800, so it won't be as *bad* as you thought.

The worst case I can think of is that your system might have a short, and the power adapter would not shut-off as soon as it would push up to 90W before it shut down. That extra 20W might allow something else to "fry" before the power adapter shut-down.

In my mind, it isn't worth worrying about, because if there is a short bad enough to cause the power adapter to fry something else, I'm not likely to fix the first problem either.

ferret1964 · Answer

Let me see if I have thr right, The PA-9 will work with the C800 with no hassle?

JersWork · Answer

They do for me. I've even used a PA-9 on a CPxH500GT and a CPiD300XT (in my C-Dock II station).

They all (PA-2, PA-6 and PA-9) provide the same voltage (20V DC) with a different max current (4.5A for the PA-9 vs 3.5A for the other two). As long as the device doesn't have any shorts, it should never try to draw more than 3.5A anyways, so you are fine.

ferret1964 · Answer

That makes sense, thanks!

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Processor performance with C-DOCK II - XP Pro

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