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Was sitting here tonight reading... and considering what I could do
with a 450 Mhz pentium if I could get my hands on one. (I've been told
people VERY often drive them 550 and higher Mhz)
I myself am using a 150 mhz pentium overclocked to 166. I was
wondering, since RAW cpu cycles are practically EVERYTHING when it
comes to povray, how many of you are using overclocked machines?
Just curious.
Johnny
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I'm running a Pentium Celeron which is supposed to be 300 Mhz with 450 Mhz.
This goes on without problems for, I don't really remember, a couple of
months now (2 or 3).
We have other machines here at work with the same setup that run since late
last year, also without problems.
But you can get unlucky: We made the experience, that approximately 1 out of
3 (or maybe 2 out of 5) such celerons do not really want to be overclocked
that much: Doing so results in Windows NT blue screens (usually quite soon
after booting or even during boot). Those we run at 366 Mhz instead.
The Celeron usually can be overclocked more than other Pentiums because it
doesn't have a casing, and thus is easier to cool.
But as far as I know, the Celeron is locked into a clock modifier of 4.5. So
you are not really totally free in your choices:
Either run the standard: 66.6 Mhz Bus times 4.5 = 300 Mhz
or the 80 Mhz Bus times 4.5 = 366 Mhz
or the 100 Mhz Bus time 4.5 = 450 Mhz
(of course it depends on which bus frequencies your motherboard supports).
So long,
Johannes.
Johnny Smith wrote in message <372C23D1.A032402D@telebot.net>...
>
>
> Was sitting here tonight reading... and considering what I could do
>with a 450 Mhz pentium if I could get my hands on one. (I've been told
>people VERY often drive them 550 and higher Mhz)
>I myself am using a 150 mhz pentium overclocked to 166. I was
>wondering, since RAW cpu cycles are practically EVERYTHING when it
>comes to povray, how many of you are using overclocked machines?
>Just curious.
>
> Johnny
>
>
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I have a intel P166 that I run in 200MHZ. As for my GFX card, i've actually
_underclocked_ it. Since my CPU can't feed to it fast enough anyway.
btw.. Cache makes difference.. I went from 256k on my MB, to 1Mb.. Difference is
big.
Johnny Smith wrote:
>
> Was sitting here tonight reading... and considering what I could do
> with a 450 Mhz pentium if I could get my hands on one. (I've been told
> people VERY often drive them 550 and higher Mhz)
> I myself am using a 150 mhz pentium overclocked to 166. I was
> wondering, since RAW cpu cycles are practically EVERYTHING when it
> comes to povray, how many of you are using overclocked machines?
> Just curious.
>
> Johnny
--
//Spider -- [ spi### [at] bahnhof se ]-[ http://www.bahnhof.se/~spider/ ]
And the meek'll inherit what they damn well please
Get ahead, go figure, go ahead and pull the trigger
Everything under the gun
--"Sisters Of Mercy" -- "Under The Gun"
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I happen to overclock my AMD K-6 233 to 266; the 233 is made with
66*3.5; so, I have 2 ways to overclock to 266 :
- 66*4, not very stable, especially with Pov, and the gain is not
important.
- 75*3.5, much more stable, and gain is much better, because, in Pov,
memory issues are as important as CPU cycles.
Cheers,
Fabien.
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I have a 333MHz Celeron OCd to 416 (runs rock-solid and quite cool). The
333 really is not a good choice for overclocking (300A is the best). It has
a locked multiplier of 5, so my next option would be
100MHz(bus)*5(cpu)=500MHz. Very few Celerons (be they 266 or 433) work at
speeds of 500MHz and beyond. I have thought of giving mine some extra
voltage and trying, but that would mean tampering with the cpu pins (unless
your MB supports cpu voltage select).
Pentiums are less overclockable, and I don't believe 550+ speeds are
common with the 450. Generally, the physical limit of the current .25 micron
manufacturing process is around 550-600MHz. But if you do manage to get to
550MHz (4.5*123fsb), you'll need high quality RAM - preferably one of the
PC133 variety. Proper cooling is also essential, more so than with Celerons.
Good luck.
Margus
Johnny Smith wrote in message <372C23D1.A032402D@telebot.net>...
>
>
> Was sitting here tonight reading... and considering what I could do
>with a 450 Mhz pentium if I could get my hands on one. (I've been told
>people VERY often drive them 550 and higher Mhz)
>I myself am using a 150 mhz pentium overclocked to 166. I was
>wondering, since RAW cpu cycles are practically EVERYTHING when it
>comes to povray, how many of you are using overclocked machines?
>Just curious.
>
> Johnny
>
>
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I have an AMD K6 233 running on a new socket 7 MBoard (one that can go up to
a 100MHz bus) can anybody help me with OCing?
mail me if you can!
Rick
Johnny Smith <joh### [at] telebotnet> wrote in message
news:372C23D1.A032402D@telebot.net...
>
>
> Was sitting here tonight reading... and considering what I could do
> with a 450 Mhz pentium if I could get my hands on one. (I've been told
> people VERY often drive them 550 and higher Mhz)
> I myself am using a 150 mhz pentium overclocked to 166. I was
> wondering, since RAW cpu cycles are practically EVERYTHING when it
> comes to povray, how many of you are using overclocked machines?
> Just curious.
>
> Johnny
>
>
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Overclocking seems to be an obsession. As soon as intel (or whoever)
publishes their new cpu, someone overclocks it.
It's true that they make a series of cpu's, then try which clock frequency
is suitable for each one and sell them that way. This way they can sell
virtually the same cpu's with a much higher price than others with a lower
frequency.
Because of this, people seem to think that they can just buy a cheaper one
and overclock it to the same frequency as the expensive ones. They never
seem to think why they are selling it with a lower clock frequency and much
cheaper.
The reason is obvious: Because it doesn't work perfectly with the higher
frequency. They sell it with a frequency which is suitable for it. If it
worked fine with the higher frequency, of course they could sell it with
that frequency and receive more money. But if the cpu becomes unstable with
those frequencies, they just can't sell them that way (it would be very
expensive to change non-working cpu's; this happened with the pentium's
division bug).
So when you overclock your cpu you are actually setting it to a level
which have been detected as unstable.
This unstability has not necessarily to be immediately visible. Everything
may seem to work just fine. You use the computer for weeks or months and
notice no problems.
But there may be problems anyway: Perhaps a program crashes sometimes. You
don't pay very much attention (programs have bugs etc, don't they?). Perhaps
you try to install the new drivers for the card you just bought, and it
doesn't succeed (it's unable to detect the card or whatever). Sometimes you
see a strange pixel on screen (programs still have bugs, don't they?).
Sometimes there's an error in the text or the spreadsheet data you have saved
on disk... And you never think that's because of the overclocked cpu (it
has been working for months, hasn't it?).
(Btw, the non-working card drivers installation because of overclocked cpu
is a true story.)
And all this for what? I once read a comparison in speed with various type
of programs with and without overclocked cpu's in a computer magazine. It
really looked like the programs were running a lot faster, but they just put
the absolute values, not the relative values (ie. the program runs n times
faster in the overclocked than in the regular cpu).
Well, I calculated it (it's easy: overclocked speed / regular speed). The
result was laughable: The programs worked about 1.3 times faster in the
overclocked computer than in the regular computer.
So you receive this minimal increase in speed at the cost of an unstable
cpu which may fail at any moment (and sometimes without you noticing it or
not paying attention to it, causing hidden and dangerous errors).
Often people think that the only problem with overclocking is the increased
temperature of the cpu. If this was true, you could take a 8086, deep-freeze
it and overclock it to 500MHz. Of course it doesn't work, no matter what the
temperature is.
The problem is of electrical nature. The cpu consists of millions of
transistors. Many transistors are put together to form logical gates, etc.
The transistors change their conductivity. They can't change their state
infinitely fast, but they need their time.
There must be a way to synchronize all those millions of transistors, and
that's what the clock pulses are doing. This means that all the transistors
are working at the speed of the slowest ones. If the clock speed is too high,
the slowest transistors don't have time to change their state in time, so
they begin to fail. This may have no effect, or it may change one bit of
data (which is sometimes enough to crash all the computer) or worse.
So you can't overclock the cpu arbitrarily. There's a physical speed limit
for the transistors.
When you overclock, you are getting nearer and nearer to this limit. You
can see when you have completely crossed the line when the computer just
doesn't work. The bad thing is that you can't clearly see, where's the
line. If you are very near, some transistors may fail sometimes very
randomly (perhaps once per minute or once per week or whatever). You may
use your computer for months without noticing and just wondering those
random-looking small errors.
And all this for about 1.3 times the regular speed...
No thanks. I have never overclocked my computer and I never will.
PS: Overclocking a 3D card may be worthy of consideration, since the only
error you will get is garbage on screen, which isn't very dangerous.
Of course there's the risc that you will burn your 3D card...
--
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/
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I underclocked my AMD 233 to 225, 75Mhz bus with 3 times multiplier.
Its faster than 233. You may beable to go higher. My MB does not
support 83Mhz or any higher. I also overclock an AMD 266 to 300.
"Rick (Kitty5)" wrote:
>
> I have an AMD K6 233 running on a new socket 7 MBoard (one that can go up to
> a 100MHz bus) can anybody help me with OCing?
>
> mail me if you can!
>
> Rick
>
> Johnny Smith <joh### [at] telebotnet> wrote in message
> news:372C23D1.A032402D@telebot.net...
> >
> >
> > Was sitting here tonight reading... and considering what I could do
> > with a 450 Mhz pentium if I could get my hands on one. (I've been told
> > people VERY often drive them 550 and higher Mhz)
> > I myself am using a 150 mhz pentium overclocked to 166. I was
> > wondering, since RAW cpu cycles are practically EVERYTHING when it
> > comes to povray, how many of you are using overclocked machines?
> > Just curious.
> >
> > Johnny
> >
> >
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I'm posting this to the group and to Mr. Mika personally.
Some may start screaming that it is off topic for the newgroup.
But I have to argue that fact. Since overclocking cpu's and generally
upping performace is of MAJOR interest to ANY playing with povray..
I say it fits RIGHT IN! Sue me!
Nieminen Mika wrote:
> Overclocking seems to be an obsession. As soon as intel (or whoever)
> publishes their new cpu, someone overclocks it.
Agreed. There's people out there with money to burn that simply
buys new motherboards/cpu combinations just to see HOW fast they can drive it.
Then publish the results. (search www.metacrawler.com for overclocking)
> Because of this, people seem to think that they can just buy a cheaper one
> and overclock it to the same frequency as the expensive ones. They never
> seem to think why they are selling it with a lower clock frequency and much
> cheaper.
To a point. I don't believe because a chip is rated at say, 100 mhz, that
it won't
RELIABLY run at 133. (or possibly higher?) Intel and other chip makers don't
rate their
chips RIGHT at, and UP TO the the point of failure. very often they leave such
a WIDE
margin of error that, well, that is what the overclockers are PLAYING with.
> The reason is obvious: Because it doesn't work perfectly with the higher
> frequency. They sell it with a frequency which is suitable for it. If it
> worked fine with the higher frequency, of course they could sell it with
> that frequency and receive more money.
Uhhh, that is EXACTLY what Intel did. In fact, it has been PROVEN that
the 150 and 166 original
Pentiums came from the same batch. They needed so many for each market.
Difference in chip?
NOTHING. NOTHING AT ALL.
> So when you overclock your cpu you are actually setting it to a level
> which have been detected as unstable.
Yes, agreed. But there ARE certain things that overclocking involves.
Things that INTEL did NOT consider and put into their "test" conditions.
For instance, Intel for obvious reasons must test their chips prior to shipment
under worst-case conditions. Such as HEAT. One of the "tricks" to overclocking
a machine REALIABLY is HEAT. You cannot drive a chip faster than what it was
intended
for, and have it HEAT up considerably. You bet it will fail. But very often
people will
drop 20-30 dollars and buy a LARGE fan and REALLY large heat sink to go with it.
Result? A chip that is running at almost room temperature. Intel can't assure
that the chip
will ALWAYS run at "room" temperature. Again, they must plan for worst case.
> This unstability has not necessarily to be immediately visible. Everything
> may seem to work just fine. You use the computer for weeks or months and
> notice no problems.
I have to agree with you there. But understand, this overclocking thing
has become
such an "art form" to some people, that utilities have been written that will
run the chip
through some pretty demanding chores, repeatedly. If there's a failure...
providing the program
is ran long enough, it WILL APPEAR. (but yes, I have seen random things go
wrong that I
definitely attributed to speed increase. I guess it's the chance you take.
> And all this for what? I once read a comparison in speed with various type
> of programs with and without overclocked cpu's in a computer magazine. It
> really looked like the programs were running a lot faster, but they just put
> the absolute values, not the relative values (ie. the program runs n times
> faster in the overclocked than in the regular cpu).
Depends... sounds to me like that article didn't have it together. And
really had NO
idea what was involved. I jumped my CPU from 150 to 166. Speed increase?
Not in any real world applications. Math intensive I did... such as povray.
But a jump of 16 mhz isn't really nothing at all. And povray didn't report any
blazing
speeds. (but then again, does it EVER???) However, there is a LOT more to
"overclocking"
than just the chip speed. There is also a matter of driving the BUS at a faster
speed.
And THIS combined with faster chip cycles is where it really starts to pay off.
The standard bus speed a few years ago was 33 mhz. (note, I did NOT say CHIP
SPEED)
People started taking the old original pentiums and upping the bus to 50 mhz.
NOW THERE
is a speed increase. PERIOD. Take the normal pentium, jump it from 150 to
166. Up the speed
of the bus from 33 to 50. Believe me, your going to see more than a 1.2 speed
increase. More like,
2.0 x and possibly higher. (You'll even see speed increases in the transfer from
the hard drive)
Bottom line, Unless you can make the chip run 100+ mhz faster, overclocking
in, and OF itself
isn't worth it. However, if you can manage to speed up the bus AND speed up the
chip at the same
time. YOU BET it's faster. A LOT faster.
>
> Often people think that the only problem with overclocking is the increased
> temperature of the cpu. If this was true, you could take a 8086, deep-freeze
> it and overclock it to 500MHz. Of course it doesn't work, no matter what the
> temperature is.
Uhhhm, your not going to believe this. But that was done already.
And yeah, it allowed them to run the chip at outrageous speeds!
What they did was take something like a 486 or something rediculous...
(I know it wasn't a pentium) and hook a compressor up to it. They
somehow surrounded the chip in a casing, then used something like compressed
ammonia or something to super cool the chip. (if I remember correctly, they
lowered the
temperature to something like -30 degrees F ) They were able to (reliably) run
this
486 or whatever it was, at something like 600 mhz. It was a pretty interesting
article.
And as far as heat is concerned, it is a big threat. The heat generated alone
can literally
cook the chip. Although there are other things to worry about. That is the
first symptom
over overdriving a chip. And must be contended with.
>
> No thanks. I have never overclocked my computer and I never will.
I understand your fear. Some of us though have seen this done realibly
SO MUCH,
that it doesn't worry us. Then again, some of us, simply don't have anything
to lose.
(are machines are so old it doesn't matter to us)
Happy tracing and best regards,
Johnny
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Nieminen Mika wrote in message <372c5bbd.0@news.povray.org>...
/a lot of stuff/
First, let me say that this all is a terrible lot of rambling on a
question that is per se relatively off-topic. But I feel I have to comment
on some of your points.
What you said about speed testing is not wholly true. Competition has
great importance in marketing strategies, and the need for a cheap CPU was
the only reason for Celeron - which is basically just a stripped-down PII.
There is _very_ little physical difference between the core of a Celeron 300
and a PII450. The main cost-cutting factor is smaller onboard cache. The
quality of the core is quite uniform over the whole range.
Secondly, you talk abut 1.3 the regular speed. Well, this is 30% speed
increase! 450MHz is 1.5 times 300, i.e. 50%. I would say this is not bad.
Some processor types handle such increases better, some worse, some not at
all. The Celeron is a special case. I will not delve into the reasons here,
but it is quite obvious when you look at how the Celeron came to be. Taking
a Celeron from 300 to, say, 375 MHz is not an issue. The physical limit of
the current .25 micron PII core is around 550-600 MHz, 450MHz is well below
that limit.
Then you speak of crashes and instability. I'm sure you've worked on
Windoze. Overclock, underclock, whatever. Windoze crashes regularly. IMO, as
long as you stay within certain limits, overclocking does not affect system
stability. And yes, deep-freezing the CPU does expand those limits. Frying
your CPU is not that easy - it locks up long before, forcing you to ease
down. You just need some common sense.
I agree that overclocking your server workstation at work is very
irresponsible. But if you know what you're doing, the risk is negligible in
any case. I have always overclocked and will always overclock. Just as I
will continue to tweak any other aspect of my system to get maximum
performance. There may be some small risk involved, but I am willing to take
that risk. It pays off.
I think I've said enough abuot this. Back to POV.
Margus
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