What's New: New Features in Version 21.x of Prime95
NEW FEATURES IN VERSION 21.x of PRIME95.EXE
New Features in Version 21.4 of Prime95
Exiting the Torture Test now prints out how long it ran.
P4 error checking was relaxed slightly to reduce false alarms.
New Features in Version 21.3 of Prime95
The program will now skip the P-1 factoring stage if another user has already
performed this step.
The Advanced/Quit GIMPS menu choice now lets you quit after current work completes
or quit immediately.
A bug was fixed in the error recovery code. After getting a "Disregard last
error" message, the user was treated to a new error on every iteration. The end
result was incorrect. The bug only affected the error recovery of the new P4 FFT
introduced in the beta version 21.2.
New features in Version 21.2 of Prime95
The program now uses the SSE2 instructions introduced on the Pentium 4 CPU.
This version is about 3 times faster than the previous version on a P4.
The program now uses the prefetch instructions on the Celeron 2, Pentium 3,
and all Athlon CPUs. This results in about a 20% performance boost on these machines.
Process priority is now set to idle. Microsoft documentation says that an
idle thread priority overrides process priority. The program's priority scheme
has always worked well. However, several Win2K users have reported that the program
works better if the process priority is also set to idle.
The program now delays calculations until 90 seconds after bootup. This lets
your machine boot up as fast as possible. This can be changed, see undoc.txt.
The default crossover between double-check assignments and first-time tests
has been increased to a 400 MHz PII.
After 5 1/2 years, a help file now exists! It is HTML Help which may have
problems on older Windows machines. If so, try downloading hhupd.exe from Microsoft's
web site.
The program used to do factoring and P-1 testing on new exponents before completing
LL tests on older exponents. This was confusing to many. The program now processes
the worktodo.ini file in sequential order. See undoc.txt on how to restore the
old behavior.
Error messages such as ILLEGAL SUMOUT, SUMINP != SUMOUT, etc. are no longer
sent to the server since the final result contains a count of how many errors
occurred during the LL test.
Some of the FFT crossover points have changed slightly.
Test/Status now outputs the day of the week each work item will complete.
Interim output lines have changed - hopefully, so they are more useful especially
to newbies. By default, output lines no longer contain the clocks count. Lines
now contain a timestamp. Benchmark timings are now output in milliseconds. These
defaults can be changed using options in undoc.txt.
A new welcome screen for new users will encourage stress testers to use the
program without reserving exponents.
There is now a menu choice that lets you unreserve a specific exponent. This
is for knowledgeable users only. You might do this if the server assigned a small
exponent and you'd rather be testing larger ones. Or the prime95 you set up on
another machine had a hard drive failure.
The Windows 9x Service menu choice has been replaced by the more general Start
at Bootup menu choice. This choice now sets registry entries to auto start prime95
on any Windows machine. WARNING: Using this option will delete any StartUp menu
shortcuts so the registry entry and startup menu do not both try to start prime95.
Prime95 will now ask for confirmation if you enter a CPU speed that differs
from the computed CPU speed by more than 4%.
The self-test menu choice was deleted - use the torture test instead.
A benchmark menu choice has been added.
The torture test code now includes more FFT lengths including smaller ones
that run completely in the L2 cache, which may increase CPU temperatures. Each
FFT size is tested for 15 minutes by default.
There are now several options in the undoc.txt for fine-tuning the torture
test's behavior.