Mobile P4 in desktop -- get out of Low Freq Mode?

MacFactor · 2010-12-18, 05:58

I tried installing a 3.06GHz P4/533MHz/512k Pentium4 (SL77P) in my old Dell Precision 360 (old cpu 2.26 GHz P4), but it turns out to be a MOBILE P4, and doesn't seem to run properly in a desktop -- I get two different inidications of clock speed (3.06GHz and 1.6GHz), and P95 benchmarks are even slower than for a 2.26GHz CPU, running one or two workers. I checked the properties at cpu-world.com and found this:
"Frequency in LFM mode (GHz) 1.6 "
<http://www.cpu-world.com/sspec/SL/SL77P.html>

LFM is part of Intel SpeedStep technology, and there seem to be some hints that it might be possible to trigger the Maximum Power Mode (MPM) through powercfg or editing logon scripts with regedit, but I can't find a detailed/coherent explanation of how to do it. It may be that it can only be done in hardware -- possibly by shorting two pins together -- but again I find only explanations that seem to be leaving something out, or apply only to one mobo, etc. To make matters worse, I'm more familiar with MacOS and UNIX than any version of Windows. Can anyone point me to a how-to, preferably for users not familiar with all the gory details of Intel CPUs and Windows? (I'm using XP + SP3)

Any help appreciated.

henryzz · 2010-12-18, 16:59

One of the easiest ways to turn off Speedstep is to turn it off in the BIOS. On your pc press F2 continuously while booting to get into the BIOS. When in there search through the menus(it will probably be a menu like "cpu features") for speedstep and turn it off. I wouldn't recomend changing any other settings unless you know what you are doing. Your pc might have come with a motherboard handbook(doubt it since it came from dell). If so that handbook should help explain the contents of the BIOS. Remember it is better to be safe than sorry with changing BIOS settings.

MacFactor · 2010-12-19, 17:27

Thanks, I found the only options for power management to be "on" and "off". Not clear if this is good enough for SpeedStep, which has multiple modes.

Just to make things more complicated, I had tried installing the 3.06 GHz chip in a different computer, but same model, as the one I am now using. After a little more hunting around for info I will try it in this box and see what happens.

MacFactor · 2010-12-19, 17:53

Here's the type of hardware fix I've seen -- http://www.sudhian.com/index.php?/ar...ing/conclusion

It may be fixable with RMClock, will give that a try.

2010-12-18, 05:58	#1
MacFactor Dec 2010 11010₂ Posts	Mobile P4 in desktop -- get out of Low Freq Mode? I tried installing a 3.06GHz P4/533MHz/512k Pentium4 (SL77P) in my old Dell Precision 360 (old cpu 2.26 GHz P4), but it turns out to be a MOBILE P4, and doesn't seem to run properly in a desktop -- I get two different inidications of clock speed (3.06GHz and 1.6GHz), and P95 benchmarks are even slower than for a 2.26GHz CPU, running one or two workers. I checked the properties at cpu-world.com and found this: "Frequency in LFM mode (GHz) 1.6 " <http://www.cpu-world.com/sspec/SL/SL77P.html> LFM is part of Intel SpeedStep technology, and there seem to be some hints that it might be possible to trigger the Maximum Power Mode (MPM) through powercfg or editing logon scripts with regedit, but I can't find a detailed/coherent explanation of how to do it. It may be that it can only be done in hardware -- possibly by shorting two pins together -- but again I find only explanations that seem to be leaving something out, or apply only to one mobo, etc. To make matters worse, I'm more familiar with MacOS and UNIX than any version of Windows. Can anyone point me to a how-to, preferably for users not familiar with all the gory details of Intel CPUs and Windows? (I'm using XP + SP3) Any help appreciated.

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2010-12-18, 16:59	#2
henryzz Just call me Henry "David" Sep 2007 Cambridge (GMT/BST) 13376₈ Posts	One of the easiest ways to turn off Speedstep is to turn it off in the BIOS. On your pc press F2 continuously while booting to get into the BIOS. When in there search through the menus(it will probably be a menu like "cpu features") for speedstep and turn it off. I wouldn't recomend changing any other settings unless you know what you are doing. Your pc might have come with a motherboard handbook(doubt it since it came from dell). If so that handbook should help explain the contents of the BIOS. Remember it is better to be safe than sorry with changing BIOS settings.

2010-12-19, 17:27	#3
MacFactor Dec 2010 2×13 Posts	Thanks, I found the only options for power management to be "on" and "off". Not clear if this is good enough for SpeedStep, which has multiple modes. Just to make things more complicated, I had tried installing the 3.06 GHz chip in a different computer, but same model, as the one I am now using. After a little more hunting around for info I will try it in this box and see what happens.

2010-12-19, 17:53	#4
MacFactor Dec 2010 11010₂ Posts	Here's the type of hardware fix I've seen -- http://www.sudhian.com/index.php?/ar...ing/conclusion It may be fixable with RMClock, will give that a try.