Pentium M 760 - Incorrect clock and bus speeds?

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DanR

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Nov 1, 2005
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Hey there.

Sorry if this has been asked before!

Notebook Hardware Controller is reporting that I have a Pentium M 760 2GHz processor correctly. However, at maximum voltage (1.356V), the reported CPU speed never reaches above 1500MHz. Yet this is a 2GHz processor. What could the problem be?

Using CPU-Z, I also noticed that my FSP speed is 99.7MHz, and my bus speed is 399Mhz. Shouldn't they be 533MHz? Sorry for my ignorance, I don't know much about this!

Thank you for your help!
 
Are you fully loading the cpu when you check the speed to ensure that it's not throttling with speedstep? Do a pifast run or something and while the system is under full load check the cpu clock with cpu-z. Also, check the power management configuration utility for your particular laptop...most centrino laptops that I've seen give you lots of configuration options for the cpu frequency, such as the max and min frequency it will use.
 
My laptop didn't come with any software, but I have the Windows power management set to Home/Office Desk.

How do I get the CPU running high? I tried when in a game earlier, but it stayed <=1.5GHz - I didn't notice the CPU load however.
 
I found Pifast, and running with CPU utilization at 100%, the clock speed was <= 1500MHz.
 
What kind of laptop is it, as that chip should have a multi of 15x...

If your FSB in BIOS is reporting as 100, then that means it is underclocked, as the 760 should be running at 133FSB, which would then give you a 15x133 = 1995, which is the 2ghz ratings. If it is stuck at 100 then it would be 15x100 = 1500, making sense...

And I think that speedstep is showing that slow speed that you are reporting, and should not be worried about, as I think the 760 will probablly hover around 800mhz with speedstep enabled, which I would see no reason to disable it, as it conserves power and battery life, with no impact on performance.
 
I have a Voodoo PC Envy n522. (www.voodoopc.com).

A couple things:
I have never reached speeds above 1.5GHz - even with a CPU load of 100%. Would this still be the result of SpeedStep? What would it take to get to 2GHz/133MHz FSB?

My BIOS has no specific options for SpeedStep. The option available is something along the lines of power management. The options for this are Enabled, Disabled, C Modes Only, and GV1/GV3 Modes Only (they might be called just V1/V3 - I can't remember).

When disabled, the highest the processor reaches is 600MHz with 100% load.
When enabled, the result is what I have described above and in earlier posts (1.5GHz).
I'm not sure of the results for C Modes and GV1/GV3 Modes, but if its necessary I'll run the same tests for those two options (which I don't think it is).

Also note that all the tests have been run with the AC line plugged in.

EDIT: Also, what does the 400/533MHz FSB speed mean?
 
DanR said:
EDIT: Also, what does the 400/533MHz FSB speed mean?
Click to expand...

This is a great question... the FSB is basically what I would consider the "true clock speed" of a system, as this is basically how fast the CPU will communicate with the memory, of course this is an oversimplified way of looking at it, thats basically what it comes down to, and what you are looking at.

Total clock speed is determined, at least for Pentiums, by its multiplier, which is locked down when the chip is made, and the FSB. Thus a P-M 760 has a 15x multiplier which should mean 15 x 133 for 1995. Which 133 is the FSB of the computer, but since Penitums are quad pumped now you think of 133 x4 = your 533fsb

Which 15 x 100 = 1500, thus a 100 x 4 = 400FSB. Which is a lot less performance compared to 533FSB chip, I would say either it is configured wrong in the BIOS, or the motherboard supplied by the company does not support the Sonoma platform for the 533FSB chips, or basically you do not have a Penitum M 760.

I would definetly be calling Voodoo up and have them explain why yours is working like a P-M 755

Also, Speedstep is not your problem, as that number is probablly correct, I am 99% sure its either you really have a P-M 755 or the FSB is just underclocked.
 
Thanks for your help, I appreciate it!

SiSoft Sandra is showing the chipset as 915PM/GM/GMS - GMS being the only one that is not 533MHz. So if it is not the GMS then the computer should be 533MHz capable, correct?

I'll talk to Voodoo tomorrow to see what's up. I hope the motherboard supports 533MHz - I'd be extremely dissapointed (at Voodoo) if they allow you to configure the computer with a 533MHz processor when it only supports 400MHz.

This also leads me to my next question - about harddrives. Interestingly enough, 7200RPM is 33% greater than 5400RPM. Is a 533MHz FSB necessary to reap the benefits of the 7200RPM drive? I hope I didn't get that option to find out it's not going to have any benefit! :)

Thanks again!
 
DanR said:
This also leads me to my next question - about harddrives. Interestingly enough, 7200RPM is 33% greater than 5400RPM. Is a 533MHz FSB necessary to reap the benefits of the 7200RPM drive? I hope I didn't get that option to find out it's not going to have any benefit! :)

Thanks again!
Click to expand...

That's really a tough question, but yes there is an obvious benefit for having a 7200RPM Hard Drive compared to the norm 5400 RPM, since there will always be a bottle neck in your system and, for most people its the access times limited by the hard drive. Even though the FSB and the hard drive read and write speeds are both needed for overall system speed, I do not think that the FSB in your case really matters, when it comes to HD access time. As its going to be the bottle neck either way, so the faster the hard drive the better in most cases. Until you get into SCSI etc where the price outweighs the performance increase

As for the chipset of your mainboard, I am pretty sure that the 915GMS is the budget version of the chipsets and is the only one that does not support the newer Sonoma platform, but a later BIOS release could have fixed that, I am currently not aware of one though.

But if that is the case I would be upset as well, wondering why they pushed a much more expensive proc (IE the 533FSB variant of the P-M) for a platform that does not even support it.

I am thinking at a high end laptop company like Voodoo that it may have been an oversight.
 
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