Getting Started: General Notes

# NOTES

Running prime95 may significantly increase your electric bill. The amount depends on your computer and your local electric rates.
It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure.
To fully utilize a dual processor machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 command line argument. Make sure the second copy also has the "Start at Bootup" option set.
Dual processor machines can also improve performance by setting processor affinity in Windows NT. Use the Advanced/Affinity dialog box to do this.
You can compare your computer's speed with other users by checking the site http://www.mersenne.org/bench.htm. If you are much slower than comparable machines, there are several utilities available (such as TaskInfo2002, http://www.iarsn.com/) that can find programs that are stealing prime95's CPU cycles.
You can get a report of your PrimeNet server account status on the web (http://mersenne.org/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box.
Information about running a local PrimeNet server is also available. See http://mersenne.org/primenet/status.shtml. If you have any questions about the PrimeNet server, you can send e-mail to primenet@mersenne.org or visit http://www.mersenneforum.org for more information.
The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. If this self-test is interrupted, the full self-test will be run when you restart prime95.
If you have overclocked your machine, I recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating.
Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes.
You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer.

> UserID=foo
> Other prime.ini entries
> Time=1-5/8:30-17:30
> Priority=1
> DiskWriteTime=30
> Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
> Priority=5
> DiskWriteTime=240

The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from the user interface.