C2D overclocking... How does it work?

All:

I'm curious how cpu overclocking works with a laptop chip that throttles down speed when on battery power or when not being taxed heavily. Is there a set multiplier in the bios for A/C mode and for Battery mode? If so, can you change the A/C mode multiplier and have it stay where you set it after rebooting like on a desktop cpu?

I am just guessing that a 1.8 c2d @ 800fsb is a 9x multiplier x200 fsb (quad pumped 200fsb = 800 fsb)?? 1.9 would be 9.5x200 and 2.0 would be 10x200??

Thanks,

AV1611 out...

 

OC'ing is not possible with most laptop chips...they can be underclocked for sure, but amonst the Intel chips only the T7600G has an unlocked multiplier. Underclocking is usually handled from within the OS when you set the power profile in your operating system, and is only possible if the BIOS support it (which all do).

Notebooks are not like desktops...your options to increase performance are VERY limited.

 

the FSB is stable, the multiplier changes but when overclocking the FSB is usually the thing that is raised when overclocking.

As for setting the multiplier, what you have in your BIOS depends on your notebook but you can lock the multiplier to one of the choices in the range by using RMClock and using the profile settings in the P-state transitions to lock the speed.

actually greg they can be overclocked but they are limited in that choice and it is quite hard to do so with varying success.

 

'Underclocking' is more of a power-saving feature. It's part of the ACPI standard and usually referred to as 'CPU Frequency Scaling'.

I have my C2D 2.0 running at 800 Mhz most of the time. If it needs more power, it bumps the speed up automatically, 800, 1200, 1600, 2000, and reduces back down to 800 when the machine is mostly idle. Works very well and keeps the notebook cool and quiet.

 

So, if a bios is specifically tuned for a laptop with a specific chip (1.8 C2D with a 9x multiplier for example), then the allowed multiplier range is going to be at the low end what the chip is supposed to run at in DC mode and at the top end what it's supposed to run on A/C, correct? Between 5x200 for 1.0Ghz (assuming that's the DC mode multiplier and resulting cpu speed) and 9x200 for 1.8Ghz?

However, if the bios is only for a line of laptops and not specifically tuned and locked (for example for Dell 1520's with 800fsb chips in them) then the highest multiplier is whatever the fastest cpu in that line of laptops needs to run at factory top speed?

 

uh no, the multipliers are locked on the CPUs themselves, they have specific range only and the BIOS does not determine this, but the BIOS can probably be modded to determine when the multipliers can be bumped or down due to temperature or CPU usage.

 

So, 1.8Ghz in a laptop means 1.8Ghz. Period.

 

yes unless you are able to use ClockGen to overclock the fsb which means finding out specific details about your mobo which may mean opening it up. the FSB can be upped but the RAM and motherboard's bus will determine how much and to a small extent the CPU too

 

I've been playing with this kinda stuff all weekend. I use all freeware. I use Notebook Hardware Control to monitor things like temp. I also set power settings to dynamic switching which means runs slower when idle or doing non demanding tasks goes to full power when needed. I use this to control heat as I don't care about battery life. This utility can undervolt some systems not mine.
ClockGen speeds up the FSB so you increase CPU and RAM speed.
RMClock is what I am using to undervolt because NHC does not work on mine. Undervolting is used to control heat which is the biggest danger of overclocking to your CPU.

Advice to anyone, when using tools to overclock or undervolt, make sure they do not start automatically with Windows, this way if anything goes wrong and system shuts down it will restart at stable factory settings, If it starts with bad settings may never start.

I was able to use ClockGen without opening my notebook up. The homepage explains how to go about this, you should not need to open up case to use.

 

yours has an nvidia chipset motherboard eh boxer? cuz it says that it shud detect them instantly if nvidia

 

Well most programs have the option you just have to make sure it's disabled at start up until you're absolutely sure it's stable.

 

Yes exactly, must always make sure the default is not to start is all Iwant to alert.

No I have ATI chipset, I also believe Nvidia has there own overclocking tool I would use if I had Nvidia, If anbody needs help after reading ClockGen homepage getting PLL with out opening case say so and I will explain.

 

ClockGen is too generic which great but also requires more attention. You might think you're raising the FSB a bit but sometimes just sometimes you're raising it more than you think or it changes more than 1 clock.

Nvidia has nTune.