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Hello,
I have an Intel i7 920.
It rapidly jumps from 50C to 80C, in full load on Povray 3.7 R3.
How could I ask Povray to use less processor?
Thank you.
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Le 05/02/2012 16:23, Mike nous fit lire :
> Hello,
>
> I have an Intel i7 920.
> It rapidly jumps from 50C to 80C, in full load on Povray 3.7 R3.
> How could I ask Povray to use less processor?
>
Not a tuning of 3.7;
Under linux, you could switch the governor for all cores from the
default ("ondemand" usually, to "performance" (full rate all time),
"conservative" (more steppy than ondemand) or "powersave" (min rate all
the time). Done with cpufreq-set command line.
Check your OS setting for powermanagement if not Linux.
Side note: 50°C to 80°C for an i7 is not the usual range, you have an
issue in your cooling-fan (my current range for i7 (970 & 980) is 20°C
to 55°C, and that's because my motherboard setting is limiting that for
55°C)
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Le_Forgeron <jgr### [at] free fr> wrote:
> Le 05/02/2012 16:23, Mike nous fit lire :
> > Hello,
> >
> > I have an Intel i7 920.
> > It rapidly jumps from 50C to 80C, in full load on Povray 3.7 R3.
> > How could I ask Povray to use less processor?
> >
> Side note: 50°C to 80°C for an i7 is not the usual range, you have an
> issue in your cooling-fan (my current range for i7 (970 & 980) is 20°C
> to 55°C, and that's because my motherboard setting is limiting that for
> 55°C)
I agree. If your CPU is running that hot in full load, it's something
you should investigate, rather than simply trying to avoid the problem
by not running any cpu-intensive programs. (Not being able to run such
programs makes your computer less useful than it could be. You shouldn't
have to worry about that.)
Note that modern CPUs usually are very hard to break even under very
strenuous circumstances because they automatically throttle down if the
temperatures raise too much. Nevertheless, it's still good to find the
source of the problem.
Older Intel CPUs (such as the Pentium4) ran a bit hot when under full
load (something like 60-70 degrees was about normal with 100% CPU load,
and something like 40 degrees when idle), but AFAIK newer CPUs such as
the i7 should be cooler even under 100% load on all cores. 80 degrees
sounds a bit too much. I don't know what the recommended temperatures are,
but I think it's probably less than 70 degrees (probably significantly
less).
There are many reasons that could cause this, such as:
- If the room temperature is very hot and humid, it could cause the PC
to overheat. However, a good-quality computer case should take care of
that, which brings us to:
- A cheap, low-quality computer case could have very poor ventilation.
Granted, there aren't many such computer cases made nowadays, but you
never know.
- In some cases wrong BIOS settings can cause the CPU fan to run at the
wrong speed, making the fan either run way faster than needed, or
altnernatively not running fast enough, making the CPU to run very hot.
This is something people are seldom aware of, but can be a real source
of overheating (or fan noise) problems. I have actual personal experience
of this. (In my case it was horrid CPU fan noise, as even a slight raise
in room temperature made it spin way too fast. Normal speed is something
between 2200 and 3000 RPM, but the wrong BIOS settings caused it to speed
up to even 6000 RPM when the room temperature was even slightly high,
completely needlessly.)
- A failing fan is, of course, also a possibility. However, if it's
spinning too slowly, your fan monitor should be showing that.
- It's not completely out of the realm of possibility that your CPU
temperature monitoring program is reporting wrong values. These monitors
need to be calibrated (but I have no idea how this is done, or even how
or if it's supposed to be done by the user).
--
- Warp
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"Mike" <msd### [at] gmailcom> wrote:
> Hello,
>
> I have an Intel i7 920.
> It rapidly jumps from 50C to 80C, in full load on Povray 3.7 R3.
> How could I ask Povray to use less processor?
>
> Thank you.
Look up 'Work_Threads' in the help file. You can set this to less than the
number of cores for your system, this will lower the temperature. Long term, you
need to look at the system cooling.
Stephen S
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Thank you all for the concern, I have already looked at some cooling solutions.
But this is the only application causing this issue.
I have some other that use the cpu fully, but the temperature never raises so
high.
It is strange.
Do you have some recommendations for good coolers that are also silent and small
(light) and not requesting to take out the mainboard in order to mount it?
BTW, the 970 & 980 are on 32nm, mine is 45nm. It is normal to be warmer.
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For two home assembled machines (an i7-920 WinXp & i7-930 Win7), I use the
"mainstream" Antec 620 Kuhler. Certainly not your high-end cooling solution,
but works quite well; e.g., the i7-930 is now somewhat overclocked to about
3400MHz - peak load (all eight threads) processor temps are slightly under
50C.
This cooler does not require motherboard removal *provided* one has access
to the back of the motherboard area where the stock fan cooler mounts.Price
is $80 or less.
"Mike" <msd### [at] gmailcom> wrote in message
news:web.4f3006ee386e01e783c6f4b30@news.povray.org...
> Thank you all for the concern, I have already looked at some cooling
> solutions.
> But this is the only application causing this issue.
> I have some other that use the cpu fully, but the temperature never raises
> so
> high.
> It is strange.
> Do you have some recommendations for good coolers that are also silent and
> small
> (light) and not requesting to take out the mainboard in order to mount it?
> BTW, the 970 & 980 are on 32nm, mine is 45nm. It is normal to be warmer.
>
>
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Thank you, Stephen S.
This helps for the moment, until I get a new cooler.
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> Thank you all for the concern, I have already looked at some cooling solutions.
> But this is the only application causing this issue.
> I have some other that use the cpu fully, but the temperature never raises so
> high.
> It is strange.
> Do you have some recommendations for good coolers that are also silent and small
> (light) and not requesting to take out the mainboard in order to mount it?
> BTW, the 970& 980 are on 32nm, mine is 45nm. It is normal to be warmer.
>
>
POV-Ray is very FPU intensive, your other programms probably don't use
the FPU as much.
If an application use the CPU at 100%, but is mostly doing logical
tests, bit-wise operations, branchings and data moves, it will hardly
make any heat.
A good example of something that can use the CPU at 100% and don't
generate heat is the "idle process" that is only a small loop...
I don't know if you checked, but some dust on the heat sink can have a
huge negative effect on the cooling. It acts as insulation and restrict
air flow.
Alain
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Am 06.02.2012 17:59, schrieb Mike:
> Thank you all for the concern, I have already looked at some cooling solutions.
> But this is the only application causing this issue.
> I have some other that use the cpu fully, but the temperature never raises so
> high.
> It is strange.
Not really. Having 100% CPU load just means that /some/ component of the
CPU is maxed out. With most applications that bottleneck is the
interface to main memory, and even that could operate much faster if it
wasn't for the inherently slow DRAM technology employed for main memory.
So even with 100% CPU load most of the silicon may still be idle most of
the time; it's just that there's no way to utilize that idle time for
anything useful.
POV-Ray, on the other hand, runs a lot of stuff straight out of the
processor cache, which uses the much faster SRAM; so it can keep the CPU
well fed with data, and really busy it with actual work, like performing
high-precision floating-point arithmetics.
Another thing to know is that the i7 CPUs probe the temperature at a
different location than earlier CPUs, closer to the actual heat sources,
resulting in a much higher temperature readout. Maybe today's CPU meters
compensate for this with a fudge factor, but at least when I bought my
own i7 they didn't, so the temperatures you're worried about do match
what I oberved myself, and may actually be safe after all.
With contemporary intel CPUs, Probably the best sign for cooling quality
is the actual CPU clock speed. The i7 auto-adjusts this according to its
current thermal situation, throttling it when in risk of overheating,
and even increasing it over the nominal speed as long as the temperature
rest assured that it feels perfectly comfortable (provided of course
you're not forcing it to that clock frequency via the BIOS).
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On 2/7/2012 19:44, Alain wrote:
> A good example of something that can use the CPU at 100% and don't generate
> heat is the "idle process" that is only a small loop...
Idle processes haven't actually run the CPU for decades. The idle process
isn't a loop - it turns off the clock.
--
Darren New, San Diego CA, USA (PST)
People tell me I am the counter-example.
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