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darienphoenix

macrumors member
Original poster
Nov 12, 2008
38
0
Hello,

I recently bought a 2.4GHz Aluminium enclosure Macbook, and love it to bits.

However, when running Windows XP Pro under Bootcamp, it seems like the CPU is underclocked. Both CPUz and CoreTemp report the CPU clock frequency as 1.6GHz, rather than the 2.4GHz it should be (multiplier at 6x, and FSB at 265 Hz).

Is this a design decision? If so, why? If not, can I get into EFI to fix the speeds?

Cheers in advance if anyone can help.
 

Skeletal-dæmon

macrumors 6502
Apr 27, 2008
369
1
The AlBooks at work don't seem to have this problem, with the exception of one which also lists only RAM in DIMM0... the tech guys are on it but haven't the foggiest why Windows is being so strange about it - when in OS X the machine is perfectly happy to denote its 2.4GHz and all 4GB RAM.

The favorite theory of the most zealous of the tech guys is that "Windows is stupid." - he got a few laughs.

(A point to remember if you read this and decide to check your RAM too... XP Home and I think its Pro SP 2 limit the RAM to 3.somethingGB)
 

darienphoenix

macrumors member
Original poster
Nov 12, 2008
38
0
The AlBooks at work don't seem to have this problem, with the exception of one which also lists only RAM in DIMM0... the tech guys are on it but haven't the foggiest why Windows is being so strange about it - when in OS X the machine is perfectly happy to denote its 2.4GHz and all 4GB RAM.

The favorite theory of the most zealous of the tech guys is that "Windows is stupid." - he got a few laughs.

(A point to remember if you read this and decide to check your RAM too... XP Home and I think its Pro SP 2 limit the RAM to 3.somethingGB)

It's listed as 1.7 GB of ram in Windows, I assume because 256MB is allocated to the video card.

Apparently I'm the only one having this problem then?
 

No1451

macrumors 6502
Oct 20, 2008
474
0
Ottawa, ON
Might be Intel SpeedStep? Happens on my desktop too, from 3.2 down to 2.1.

And if anyone DOES say its cause Windows is stupid, well you have your answer.

Also to answer that RAM supposition, its not Windows that makes it limited, its 32bit windows that limits your max amount of ram, the 4gb I have in my desktop is all showing up perfectly(cause its 64bit)
 

Jollins

macrumors regular
Jun 9, 2006
195
0
Sounds like power management to me. It improves battery life and keeps the temps down, but it will ramp up to full speed when something needs it so you shouldn't notice a performance loss. OS X does this too.
 

dbdynsty25

macrumors regular
Nov 9, 2008
147
2
Thousand Oaks, CA
Sounds like power management to me. It improves battery life and keeps the temps down, but it will ramp up to full speed when something needs it so you shouldn't notice a performance loss. OS X does this too.

Exactly. If you change your power profile in the Windows Screen Saver section to Desktop instead of Laptop...it goes back to 2.4ghz.
 

Skeletal-dæmon

macrumors 6502
Apr 27, 2008
369
1
Hmm I'll give this a go tomorrow and see how it effects the AlBook. Still not sure about the RAM, might just be an odd DIMM slot.
 

darienphoenix

macrumors member
Original poster
Nov 12, 2008
38
0
Ah, I forgot about SpeedStep. I haven't had it turned on in a PC for years, because I overclock all my desktops, and this is the first time I've had Windows on a Macbook using Bootcamp rather than a VM.

Thanks for the help, I'll load the CPU next time and check if it goes back up to 2.4GHz.
 

reeveah

Suspended
Oct 23, 2008
88
11
Ah, I forgot about SpeedStep. I haven't had it turned on in a PC for years, because I overclock all my desktops, and this is the first time I've had Windows on a Macbook using Bootcamp rather than a VM.

Thanks for the help, I'll load the CPU next time and check if it goes back up to 2.4GHz.


Hi,

I've bootcamp the 2.4ghz MB alu running 4ghz but the processor only reflects 1.58ghz.

How do i rectify this problem then?
 

aznguyen316

macrumors 68010
Oct 1, 2008
2,001
1
Tampa, FL
Try reading the topic?

heheh

but yeah change the power setting of your OS. I didn't check mine before I changed it, but intalled nvidia system tools and mine shows correct clock. I also OC'ed mine in bootcamp though to 299FSB I forget the multiplier (7.5?) to ~2.3Ghz and stays cool thanks to SMC fan on the OS X side. And OC'ed the GPU a bit too. Just for gaming.
 
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