# Found the equation for Seti w/u:mhz ratio

#### joecool85

##### macrumors 65816
Original poster
It takes 578mhz to do one w/u a day. Therefore that would mean an 867mhz would do 1.5 a day (accurate, thats what my PB does) and a 266mhz would do one every 2.1 days, also accurate. Someone compare my equation to their computer. All you do is take your CPU speed and divide it by 578. It *should* give you roughly the w/u you complete in one day.

#### zv470

##### macrumors 6502
Don't you mean you found the scale factor? That equation is pretty standard? No?

#### Dane D.

##### macrumors 6502a
You are wrong

It takes 578mhz to do one w/u a day. Therefore that would mean an 867mhz would do 1.5 a day (accurate, thats what my PB does) and a 266mhz would do one every 2.1 days, also accurate. Someone compare my equation to their computer. All you do is take your CPU speed and divide it by 578. It *should* give you roughly the w/u you complete in one day.
First off, every work unit is different. Second did you take into account that if SETI runs in Blank screen mode it runs WUs faster? Of course not. I run a B/W G3/300 in blank screen mode and can complete a WU in 20-22 hrs. I have stated before that in Blank screen mode WUs can be crunched much faster than screensaver mode. I figure my WU times by looking at the percentage of WU completion per hour. 300MHz = roughly 5% per hour. 450/466 MHz = roughly 7.5% per hour. 1.25GHz = 16% per hour. Take your 100 and divide by the average completion per hour---100/7.5=13.33hrs.

#### joecool85

##### macrumors 65816
Original poster
What is blank screen mode? I don't run mine in screensaver mode, I turn it on and set my computer to stay on and just shut off my monitor.

**edit**
And I'm pretty sure that seti units are always the same size, its folding ones that aren't.

#### aussie_geek

##### macrumors 65816
joecool85 said:
What is blank screen mode? I don't run mine in screensaver mode, I turn it on and set my computer to stay on and just shut off my monitor.

**edit**
And I'm pretty sure that seti units are always the same size, its folding ones that aren't.
Yes, they are all the same size but the amount of processing required to complete the task differs from unit to unit.

My G5 did a work unit in 45 mins one time. On average it takes less than 2 hours / unit . The command line app would be even faster.

I don't run it any more as it apparently rips hard drives and I couldn't be bothered setting up the RAM disk method. It also turns my G5 into a bit of a wind tunnel some times.

aussie_geek

#### Dane D.

##### macrumors 6502a
What?

I don't run it any more as it apparently rips hard drives and I couldn't be bothered setting up the RAM disk method. It also turns my G5 into a bit of a wind tunnel some times.
BS. Where are you getting your info? The CPU does all the work, the HD only stores the info crunched to send back to SETI. I am coming up on my 1st yr anniversary and no problems. My main machine is the G3/300, 6 yrs old and still purring like the day it was new. Just make sure you have a good air flow through the box and everything will be fine. It is the peps that use PowerBooks that burn up your machine, probably because they don't raise it off the table to get air underneath it. I use 1/2" rubber feet and a small desk fan blowing across the unit to cool my PowerBook the fan hardly comes on. My temps never exceed 109ºF in my G3.

#### aussie_geek

##### macrumors 65816
Dane D. said:
BS. Where are you getting your info? The CPU does all the work, the HD only stores the info crunched to send back to SETI. I am coming up on my 1st yr anniversary and no problems. My main machine is the G3/300, 6 yrs old and still purring like the day it was new. Just make sure you have a good air flow through the box and everything will be fine. It is the peps that use PowerBooks that burn up your machine, probably because they don't raise it off the table to get air underneath it. I use 1/2" rubber feet and a small desk fan blowing across the unit to cool my PowerBook the fan hardly comes on. My temps never exceed 109ºF in my G3.
What happens is when you are processing a work unit, the result from each process is written back to disk. Although the data units are small (about 350kb) your Mac is continually reading / writing the data from the same sector of the disk. Think of it as a bush track. Although there is lots of dirt there, over time the people who walk through there make a groove.... Do you want this to happen to a \$200 hard drive?

Now, lets say that data unit is somehow fragmented on your drive. Imagine all the work the drive heads have to do to read / write a data result.

This is why you should set up a ram disk - it saves your hard drive and actually speeds up the process. It is always faster to read / write from ram than it is to a HD.

aussie_geek

edit - although I do think distributed computing is a great solution to solving problems, I can't see myself being that dedicated setting up a box fan to cool my computer so I can pump out 300 work units a year....

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