# overclocking & compilation failure

## OPelerin

I get some strange behaviors.

My home pc is based on asus p4c800-e deluxe and a p4 3000@3600 ( bus at 240 mhz)

I dont get any issues on XP ( when I play on some intensive 3D games)

But, once a while, I can't compile some programs under gentoo ( eg kdebase/kdelibs).

In the meanwhile, it works when I revert computer speed to 10 % overclocking.

Since I dont experience same issues under heavy gaming on XP, it make no sense Gentoo compilation fails.

Any 'scientific' explanation?

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## hds

 *OPelerin wrote:*   

> 
> 
> Since I dont experience same issues under heavy gaming on XP, it make no sense Gentoo compilation fails.
> 
> 

 

this is not gentoo specific but normal on any linux system. if you are compiling source the CPU gets up to 100% CPU Load. you do not have such circumstances using games on XP.

if you overclock your CPU you do so at your own risk. corrupted data will be the case also on WhimpDos, for example if you archive (zip) huge files. unfortunately you will notice this when you least expect it, and when it is too late   :Laughing: Last edited by hds on Mon Sep 13, 2004 8:23 pm; edited 1 time in total

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## NeddySeagoon

OPelerin,

Not to put too fine a point on it, if your 3D rendering is wrong you won't notice until it gets quite bad.  The odd pixel there and there will be missed.

Now if those pixels are in your compile it matters a great deal, You can't even afford to have even one wrong.

Linux works the hardware much closer to the limits than Windows, so there is less scope for overclocking.  Thus a stable overclock on windows may not even boot linux.

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## MrApples

i have been doing a lot of research on this and found that it is safe to overclock, but it must be very highly tested

for instance, once you get a setting that you think is stable, run mprime and or cpuburn for 12+ hours until you get no errors, and then drop the oc down a couple of notches afterwards for extra insurance

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## Gentree

Yep , I'll go along with all that.

I found the first thing to go wrong when I pushed my overclocking was after about 90 mins of a major compile.

Do thorough testing then pull back as suggested.

I also think Linux is much more rigourous than win so the errors throw a fault straighaway.

BTW my AthlonXP-1800 (16.7Ghz) is now clocking at 2.204 GHz and perfectly stable since March. So you can run a stable system if you are rigourous about testing.

HTH. 

 :Cool: 

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## devast

I agree too.

If the overclock is well tested you won't have any problem with compiling... i recommend using prime95 in torture test funciton for at least 24h. If it fails you may set the fsb lower or give some +vcore to the CPU. I've done it too... my 1700+ Athlonxp (1466Mhz) is now running at 2150Mhz with vcore 1.65V or 1.70V @ 1.80V. It's quite stable i compiled my whole system with gentoo of course  :Smile:  Also you should check the ram in overclocking situation... just emerge memtest86+ and edit your grub/lilo config  :Smile: 

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## Gentree

memtest86 first, make sure your RAM is sound and capable of the speed.

next use cpuburn. This suite of tests lets you stress different components , MMX, BX (southbridge) and P6 series instructions.

I found the BX test was the first to show problems when I pushed the o/c too far.

Obviously keep a close eye on CPU temp if you start pushing clock speed or above all if you up the voltages to get a bit more. That really starts to create heat.

All you need is on portage.

Have fun, but be careful. (As your ma would say!)

 :Cool: 

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## mercurator

In my experience Prime95 and Memtest86 aren't stresfull enough. I overclocked my celeron 2700 to 3200MHz. I ran memtest for two hours and then Prime95 for additional six hours. Everything worked fine, no errors what so ever. Then I went to my freshly installed gentoo end started emerging kde. FAILED!!! The compilation stopps at some point, but not always at the same place, which is a clear indication that the machine is not stable enough. My addvice is to drop a few FSB MHz from the last (Prime95 & memtest86) known stable setting. Then GCC will work fine, otherwise you're asking for trouble.

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## Gentree

Memtest86 is not a stress tool, it is a memory test , hence the name.

The point is you need to know you dont have a dodgy memory cell before you start, and then check again once you up the clock speed. Again you're not stressing with memtest, you are testing the memory at the new clock rate.

and no prime95 is not a good stress tool either it only does a very limited use of the system , that's why I recommend cpuburn which is a thorough stress tool suite, designed uniquely with that purpose in mind. 

If you can get burnBX and burnP6 to run for 15 minutes each you can keep you o/c settings where they are , emerge kde as often as you like and your system will thank you for being so nice.

Then you can unmerge kde and it will thank you again and kiss your bottom.

 :Cool: 

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## drescherjm

 *Quote:*   

>  I ran memtest for two hours and then Prime95 for additional six hours. Everything worked fine, no errors what so ever.

 

This is the problem. I have had bad memory that took memtest86 several days to find. A few hours with memtest86 just is not enough to assume a system is stable. Also unless you run the torture test in prime95 it will not be a good test of the system memory as it will only use a small fraction of your memory in a normal test.

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