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Old 2009-04-11, 03:53   #1
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Default Changing priority level

How do I change the priority level in Prime95?
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Old 2009-04-11, 05:37   #2
cheesehead
 
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May we ask why you want to?

Prime95 is almost completely compute-bound/CPU-bound. That means that if it's not at lowest priority, it will shut out any lower-priority tasks, for long periods of time, except during the < 1% of the time when it's reading or writing from disk or displaying a message. Also, it will strongly compete for CPU time with whatever else is on its priority level.

Raising Prime95's priority will not make _it_ run appreciably faster, but may make other tasks on your system run m-u-c-h slower.

One of the main principles of Prime95 is to interfere as little as possible with any other tasks on the system.

If 99% of the CPU time (i.e., Prime95) is at priority 1, say, and 1% is at priority 2, the priority 2 tasks will stiil be as responsive as though prime95 were not running. If, instead, 99% of the CPU time (Prime95) is at priority 2, and 1% is at priority 1 (or other priority-2 tasks), the priority-1 tasks (or other priority-2 tasks) will be very slow, but you won't see any more than a 1% speedup in prime95.

If your motive is to keep a screensaver from slowing down Prime95, it would be better to prevent the screensaver from running than to mess with Prime95's priority.

If you still think you have a good reason, will you please explain it?

Last fiddled with by cheesehead on 2009-04-11 at 05:39
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Old 2009-04-11, 06:33   #3
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I think we should still tell him/her how to do it.

Click on Test -> Worker Windows...
Priority can be adjusted on the second line. I've never done it before though so I don't know whether it'll work or have serious consequences.
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Old 2009-04-11, 14:20   #4
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Quote:
Originally Posted by cheesehead View Post

If your motive is to keep a screensaver from slowing down Prime95, it would be better to prevent the screensaver from running than to mess with Prime95's priority.
That is exactly why. I would rather keep my screen saver running. Perhaps I should withdraw from participation in GIMPS?
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Old 2009-04-11, 17:54   #5
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Some REAL screensavers do not use any processing power : "Blank" for instance. Since it blackens the screen it really saves it and the machine is locked if you wish so.

Jacob
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Old 2009-04-11, 19:19   #6
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Quote:
Originally Posted by Unregistered View Post
Perhaps I should withdraw from participation in GIMPS?
No, no, no -- I was just expressing my own opinion about screensavers, because I personally don't care for them, not because there's any important conflict between GIMPS and screensavers. I should have made that clearer.

You're entitled to your own preference in that regard, and there's no reason, now that I see your motive, why GIMPS participation precludes your wanting to adjust priorities so that the screensaver and Prime95 co-exist in the relationship you desire.

Quote:
Originally Posted by hockmeng View Post
I think we should still tell him/her how to do it.
Oh, yes ... the only reason I didn't was that I forgot how.

Last fiddled with by cheesehead on 2009-04-11 at 19:23
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Old 2009-04-11, 19:48   #7
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Should not use an active screensaver when doing Distributed Computing.
Rather use blank screen, or better yet, no screensaver and use the power options to turn off the Monitor after x minutes of time.

Using an active screensaver is like putting a brick on the gas pedal of a vehicle, while in neutral and engine running.
JMHO

Last fiddled with by IronBits on 2009-04-11 at 19:51
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Old 2009-04-11, 20:17   #8
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But let's recall that Prime95 itself was distributed in "screensaver" form (among others) for Windows 3.1

Similarly, other distributed computing projects might (for various, perhaps legitimate, reasons) be distributed in the form of "screensaver", so as to be easily plugged-in that way to the user's system.

So, a GIMPS user's screensaver might be saving more (say, a cure for cancer) than only a screen!

Last fiddled with by cheesehead on 2009-04-11 at 20:20
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Old 2009-04-11, 21:40   #9
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Oh ya, forgot about that! Not the most efficient way to run a client for a project, but at least it's doing something constructive.
Good point!
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Old 2009-04-12, 00:10   #10
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Quote:
Originally Posted by cheesehead View Post
So, a GIMPS user's screensaver might be saving more (say, a cure for cancer) than only a screen!
Yeah, but then their CPU time is only being used for GIMPS while the screensaver is not on. Of course, that does mean that their CPU is being used for something at all times, which is better than the active-time waste that the screensaver method produces.
Anyway, as for the topic, if you need to run a screensaver, (and the power settings for the monitor, as mentioned above, won't work for some reason) choose Blank and keep Prime95's priority at 1. If the screensaver is for a DC project, stop running it or leave Prime95 on at priority 1.

Last fiddled with by Mini-Geek on 2009-04-12 at 00:15 Reason: added something ontopic :P
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Old 2009-04-12, 14:46   #11
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Quote:
Originally Posted by Unregistered View Post
That is exactly why. I would rather keep my screen saver running. Perhaps I should withdraw from participation in GIMPS?
Just to add another note, I think that most of us do not care about the screen saver is because on an LCD screen, the screen saver does not "save the screen" but is just another prop. Something which has been carried over from the days when we still used CRT monitors.

If you're still using a CRT monitor, then a screen saver does help prolong the lifetime but I think you can get around that by just switching off the monitor.
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