I just made my DX2/66 a DX2/75!?!?!

I just made my DX2/66 a DX2/75!?!?!

Post by Shoel Perelm » Wed, 13 Jul 1994 10:05:25



After reading about somenoe saying they are running their Intel DX2/66 at
80 mhz, I decided to give it a try with my AMD 66... I changed around the
jumpers on the motherboard and my system said 75Mhz CPU on the bootup
screen!!! I was elated!  I HAD to see if this was really more performance
or just a bull*inflated Mhz rating...

I compiled my linux kernel at 66 mhz... Took 124 seconds... After my "modification" it compiled in only 97 secnds!!!! wowow!!!  

Is this like puniching holes in DD disks to make them HD only to have them
lose all their data in a few weeks?  What is the downside to ru nning my
CPU a little too fast??  Or am i just getting FREE extra performance???


 
 
 

I just made my DX2/66 a DX2/75!?!?!

Post by olav woelfelschneid » Wed, 13 Jul 1994 17:50:43



> After reading about somenoe saying they are running their Intel DX2/66 at
> 80 mhz, I decided to give it a try with my AMD 66... I changed around the
> jumpers on the motherboard and my system said 75Mhz CPU on the bootup
> screen!!! I was elated!  I HAD to see if this was really more performance
> or just a bull*inflated Mhz rating...

> I compiled my linux kernel at 66 mhz... Took 124 seconds... After my "modification" it compiled in only 97 secnds!!!! wowow!!!  

> Is this like puniching holes in DD disks to make them HD only to have them
> lose all their data in a few weeks?  What is the downside to ru nning my
> CPU a little too fast??  Or am i just getting FREE extra performance???

This is hard to say, since even experts are argueing on it...
The arguments:

- overclocking may overheat your cpu causing a BIG loss of cpu lifetime.
+ Modern 486/66 reach only 55C surface temp, allowed are 85C, so you have
  enuff room....

- even if the surface has only 85C, there may be local 'hot spots' inside
  the cpu which will cause it to break only at a few points.
+ Modern cpus won't build hot spots.
- (who knows?)

+ Who bothers reducing the lifetime from 200 years to 10 years? Who would
  be interested in a 486 after 10 years anyway?

- The processor may malfunction if overclocked, and you will spend hours
   on searching for the bug in your software...

- The FPU mostly is more critical than the main cpu, do you really like
  wrong calculations.

- Usually the cpu's are built, and then tested: The good ones get
  the 66MHz mark, the bad ones only 40Mhz and so on...
   So if you overclock, you may be out of luck.

+ Lots of people have done it and are lucky...

So decide for yourself if you like to do it or not...

Some hints:
* BE SURE to have an active heatsink on your cpu, it should have a small fan
  on it. Maybe you should check the CPU temperature after doing some heavy
  calculations, integer and with the FPU.
* Some people say using a peltier heatsink is ridiculous, cause it cools the
  cpu case too much, causing a too big temperature difference between inside
  and outside which may break your chip into pieces.
* REALLY: BE SURE TO COOL YOUR CPU PROPERLY!!! The maximum is 85C

Note:
IF you have access to german computer magazines, consider buying c't 8/94
which has an article about cpu overclocking.

Ok, try it if you like, BUt DON'T BLAME ON ME IF YOUR SYSTEM BREAKS, I GIVE
NO WARRANTY FOR THE TIPS ABOVE. (Read the usual GNU disclaimer :)

Hope it helps,
--
/======================================\
| Olav "Mac" Woelfelschneider          |

+--------------------------------------+
| I refuse to grow up,                 |
| I don't want to lose my humor...     |
\======================================/

 
 
 

I just made my DX2/66 a DX2/75!?!?!

Post by MARKUS REGN » Wed, 13 Jul 1994 18:02:21



> After reading about somenoe saying they are running their Intel DX2/66 at
> 80 mhz, I decided to give it a try with my AMD 66... I changed around the
> jumpers on the motherboard and my system said 75Mhz CPU on the bootup
> screen!!! I was elated!  I HAD to see if this was really more performance
> or just a bull*inflated Mhz rating...

> I compiled my linux kernel at 66 mhz... Took 124 seconds... After my "modification" it compiled in only 97 secnds!!!! wowow!!!  

> Is this like puniching holes in DD disks to make them HD only to have them
> lose all their data in a few weeks?  What is the downside to ru nning my
> CPU a little too fast??  Or am i just getting FREE extra performance???



The Intel processors are known to be able running overclocked without
any damage as long as they are protected thermally by heat sink and fan
or better devices.
They are very thermal tolerant and some guys have them running overclocked
for more than 2 years without trouble.

The AMD processors havn't been tried out for now, I think you're one of
the first.
(The rest of the motherboard only will have timing problems but no damage.)

Good luck!

------------------------------------------------------------------------------

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Experimentelle Physik III/MBE           fax:   ++49/931/888-5142
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I just made my DX2/66 a DX2/75!?!?!

Post by George W. (Bi » Thu, 14 Jul 1994 13:30:22



>Is this like puniching holes in DD disks to make them HD only to have them
>lose all their data in a few weeks?  What is the downside to ru nning my
>CPU a little too fast??  Or am i just getting FREE extra performance???

It's like punching holes in the side of your CPU. You're now operating the
machine outside spec. More or less, I've seen some machines work just fine
this way, and some that eventually blow skyward, literally, as something
overheats. With the increased performance comes all the usual suspects of
heat, tolerance, and failure.
 
 
 

I just made my DX2/66 a DX2/75!?!?!

Post by Tae Ho Y » Thu, 14 Jul 1994 19:50:55


: After reading about somenoe saying they are running their Intel DX2/66 at
: 80 mhz, I decided to give it a try with my AMD 66... I changed around the
: jumpers on the motherboard and my system said 75Mhz CPU on the bootup
: screen!!! I was elated!  I HAD to see if this was really more performance
: or just a bull*inflated Mhz rating...

: I compiled my linux kernel at 66 mhz... Took 124 seconds... After my "modification" it compiled in only 97 secnds!!!! wowow!!!  

Is that right???  124 seconds! and 97 seconds!
Is that for a full rebuild?

Are you sure, you are not running 660 --> 750 MHz?

tae.

: Is this like puniching holes in DD disks to make them HD only to have them
: lose all their data in a few weeks?  What is the downside to ru nning my
: CPU a little too fast??  Or am i just getting FREE extra performance???


:  

 
 
 

I just made my DX2/66 a DX2/75!?!?!

Post by Glen Mart » Thu, 14 Jul 1994 21:45:15



>After reading about somenoe saying they are running their Intel DX2/66 at
>80 mhz, I decided to give it a try with my AMD 66... I changed around the
>jumpers on the motherboard and my system said 75Mhz CPU on the bootup
>screen!!! I was elated!  I HAD to see if this was really more performance
>or just a bull*inflated Mhz rating...

>I compiled my linux kernel at 66 mhz... Took 124 seconds... After my "modification" it compiled in only 97 secnds!!!! wowow!!!  

>Is this like puniching holes in DD disks to make them HD only to have them
>lose all their data in a few weeks?  What is the downside to ru nning my
>CPU a little too fast??  Or am i just getting FREE extra performance???



It was tested at 66. It wasn't tested at 75.
You may experience heating problems and perhaps have trouble with your cpu
clock.
--

::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
If you can just get your mind together then come on across to me. We'll hold
hands and then we'll watch the sunrise from the bottom of the sea. J Hendrix
 
 
 

I just made my DX2/66 a DX2/75!?!?!

Post by Mark Lo » Thu, 14 Jul 1994 23:00:56



>The Intel processors are known to be able running overclocked without
>any damage as long as they are protected thermally by heat sink and fan
>or better devices.
>They are very thermal tolerant and some guys have them running overclocked
>for more than 2 years without trouble.

>The AMD processors havn't been tried out for now, I think you're one of
>the first.
>(The rest of the motherboard only will have timing problems but no damage.)

My motherboard is good for up to 50Mhz operation (100Mhz DX2/DX4),
and has no timing problems at all with the AMD486DX2-66 running at 80Mhz.

The CPU itself is heatsinked and has an attached cooling fan, and thus far
(1 week) seems pretty happy.  Maybe it will only last 5 years instead of 20,
but I'm likely to have upgraded again before that time anyways.  If it dies
earlier due to this mistreatment, well.. them's the breaks.

Just for a little added risk, I'm still driving my ISA cards at 1/4 CLKIN,
which at 40MHz (for 80Mhz DX2) gives about 10Mhz, instead of the more standard
8.25Mhz (approx) that they got from 1/4 CLKIN at 33Mhz (for 66Mhz DX2).
Experience has shown that most cards will tolerate the 10Mhz ISA bus,
with a resulting gain of up to 25% in raw data throughput (think "disk drives"),
but I have had cards fail (and *die*) at higher clocks such as 12Mhz.

With 512KB of external CPU cache, running in "copyback" mode (another BIG perf.
gain for many applications), this system feels very snappy.  A full kernel
rebuild last night (not including 'make dep') took 793 seconds (with -j3
hacked into the top level Makefile), raw data throughput from my IDE drive
clocks in at about 1.73MByte/sec, and IOZONE reports ext2 filesystem throughput
of 1.53MB/sec writing and 1.62MB/sec reading.
--

 
 
 

I just made my DX2/66 a DX2/75!?!?!

Post by Brad Coom » Fri, 15 Jul 1994 00:51:02



> After reading about somenoe saying they are running their Intel DX2/66 at
> 80 mhz, I decided to give it a try with my AMD 66... I changed around the
> jumpers on the motherboard and my system said 75Mhz CPU on the bootup
> screen!!! I was elated!  I HAD to see if this was really more performance
> or just a bull*inflated Mhz rating...
> I compiled my linux kernel at 66 mhz... Took 124 seconds... After my "modification" it compiled in only 97 secnds!!!! wowow!!!  
> Is this like puniching holes in DD disks to make them HD only to have them
> lose all their data in a few weeks?  What is the downside to ru nning my
> CPU a little too fast??  Or am i just getting FREE extra performance???


Don't know what you did, but I would think you're playing with fire.  You
could burn up your chip.  To me, it's like tweeking that*on your
turbo engine in your car.  You'll get more performance, but you'll burn
up your engine.

Why do you think they don't take the same 486/25 & put a high frequency
crystal on the motherboard to make the chip run at 486/150 instead of
redesigning the chip?

If it works, more power to you...Otherwise, I think Intel 486DX2/66
chips  are running about $600 or so now...

By the way, this is the MSDOS.PROGRAMMER newsgroup...Try the INTEL
newsgroup...

My 2 pennies...
--Brad

 
 
 

I just made my DX2/66 a DX2/75!?!?!

Post by Scott C. Cottril » Fri, 15 Jul 1994 02:24:34


: I compiled my linux kernel at 66 mhz... Took 124 seconds... After my "modification" it compiled in only 97 secnds!!!! wowow!!!  

Did you flush the cache before rebuilding the kernel?

 
 
 

I just made my DX2/66 a DX2/75!?!?!

Post by Mark Roge » Fri, 15 Jul 1994 04:01:19



Quote:

> - Usually the cpu's are built, and then tested: The good ones get
>   the 66MHz mark, the bad ones only 40Mhz and so on...
>    So if you overclock, you may be out of luck.

  + The demand for the bad ones (being cheaper) exceeds the availability
    (they're aren't that many "bad" chips being made - Intel (etc) are
    actually quite good at their job :) so lot's of good ones get labled
    with a lower rating and sold at the lower price. If you got a good
    CPU labled as a bad one then you should be okay (with proper cooling,
    etc).

Mark.
--

function MeaningOfLife :integer; begin MeaningOfLife := 6 * 9; end;

 
 
 

I just made my DX2/66 a DX2/75!?!?!

Post by Brett Co » Fri, 15 Jul 1994 07:05:57



>Is this like puniching holes in DD disks to make them HD only to have them
>lose all their data in a few weeks?  What is the downside to ru nning my
>CPU a little too fast??  Or am i just getting FREE extra performance???

The possible downsides are that your CPU might run too hot at the
new speed, and it also might be less reliable than before.  I'm
not sure how significant the heat problem really is, though you
can be fairly sure it will now run 75/66 = 14% hotter.  A heat
sink or CPU cooling fan might be in order.  I'd worry more about
the possibility of unreliable operation.  You might experience
occasional crashes or odd behavior due to the chip, RAM, etc not
quite working at that speed.  If the 14% improvement in performance
is worth the risk, go for it.

-Brett

--
+------------------------------------------------------------+

| Integrated Information Technology Inc. (408) 727-1885 x367 |

 
 
 

I just made my DX2/66 a DX2/75!?!?!

Post by Alexander Pe » Fri, 15 Jul 1994 07:50:14


[I made my 486/66 a 486/75, etc]

Quote:

>Don't know what you did, but I would think you're playing with fire.  You
>could burn up your chip.  To me, it's like tweeking that*on your
>turbo engine in your car.  You'll get more performance, but you'll burn
>up your engine.

>Why do you think they don't take the same 486/25 & put a high frequency
>crystal on the motherboard to make the chip run at 486/150 instead of
>redesigning the chip?

What I have heard (yes, this is only rumor) was that Intel makes the
chips for a certain speed, then tests what speed they can actually run
at.  Some run slower because of manufacturing defects, so they sell these
as the lower-speed chips.  I suppose if they need more lower-speed chips
they sell the better ones anyway, so your 486 MIGHT be capable of running
at a higher speed.  I don't know if they are designed for 75 MHz or not.  
Of course, they are talking about those clock-tripled models, so maybe.

This is only stuff I have heard from others.  I do know of one individual
who put a faster clock crystal into his Mac LC and has mostly no problems
with it.  I don't know if that helps, that is is a different processor
and manufacturer after all.

 
 
 

I just made my DX2/66 a DX2/75!?!?!

Post by Rainer Dey » Fri, 15 Jul 1994 07:14:19


Is this possible at all for 16MHz 386SX's?

--
+---------------------------------------------------------+
| "I don't work for HP, nor for anyone else, and if I did |
| I wouldn't speak for them."                             |

+---------------------------------------------------------+

 
 
 

I just made my DX2/66 a DX2/75!?!?!

Post by Shoel Perelm » Fri, 15 Jul 1994 09:07:55




>: I compiled my linux kernel at 66 mhz... Took 124 seconds... After my "modification" it compiled in only 97 secnds!!!! wowow!!!  
>Did you flush the cache before rebuilding the kernel?

I did a complete reboot, ofcrouse.. I'm not crazy euf to change the jumpers
while the system is still running. . (although I'v changed HD controllers
whiel my system was running... wihtout realizing the system was on :)


-shoel

 
 
 

I just made my DX2/66 a DX2/75!?!?!

Post by Trond Sol » Thu, 14 Jul 1994 04:14:18



> After reading about somenoe saying they are running their Intel DX2/66 at
> 80 mhz, I decided to give it a try with my AMD 66... I changed around the
> jumpers on the motherboard and my system said 75Mhz CPU on the bootup
> screen!!!
> What is the downside to running my
> CPU a little too fast??  Or am i just getting FREE extra performance???

You are getting FREE extra performance and HEAT in the processor. You better
mount a ice-cap to cool it a bit.

Trond
-------

 
 
 

1. Linux on Winbook DX2/50 & DX4/75

Hi,

Has anyone gotten Linux to run on either of these Winbook laptops? I'd love to
just order up a DX4 for myself, but without knowing as to compatibility, well,
I simply can't take the risk. BTW, if anyone has in fact gotten Linux to run
without major problems, is there any provision in the current version of
XFree86 for using the special capabilities of the Western Digital RocketChip
graphics accelerator that's used in the Winbooks? Also, what's the overall
performance like?

Thanks in advance.

--
Zack T. Smith
Creator of MacShell(tm) - the C Shell for the Mac
Email me if you'd like a demo copy.

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