Prime95 version 27.7 / 27.9

[TObject]

Is there a way to switch to a larger FFT manually in the middle of a primarily test?

[Prime95]

Originally Posted by TObject

Is there a way to switch to a larger FFT manually in the middle of a primarily test?

You can, but there is no need to do that. The smaller FFT size is chosen because it will be faster, albeit a bit whiney.

[JTL]

I'm sorry if this was asked earlier but I can't find this concern if so...


I see at http://www.mersenneforum.org/gimps/ there is p95v279.MacOSX and mprime277-MacOSX

Is the difference between the mac OS X mprime v27.7 and prime 95 v27.9 only for the GUI of prime95?

Otherwise, is there an mprime for mac os X at v27.9 that I can get?

I'm interested in mprime over prime95 so that I can script the execution and timing of mprime via unix-related utilities in Mac OS X.

[Mark Rose]

Originally Posted by JTL

I'm sorry if this was asked earlier but I can't find this concern if so...


I see at http://www.mersenneforum.org/gimps/ there is p95v279.MacOSX and mprime277-MacOSX

Is the difference between the mac OS X mprime v27.7 and prime 95 v27.9 only for the GUI of prime95?

Otherwise, is there an mprime for mac os X at v27.9 that I can get?

I'm interested in mprime over prime95 so that I can script the execution and timing of mprime via unix-related utilities in Mac OS X.

If you have a Haswell processor, the v27.9 version may give you better performance if:
* You have fewer than 4 real cores
* You have 4+ real cores with RAM faster than dual channel 2000 MHz (dual channel 1600 MHz RAM can barely keep 3 cores of my i7-4770 saturated when running v27.9).

If you have one of those Haswell Mac Pros with quad channel RAM, you probably want to talk Prime95 into compiling a version for you.

[sdbardwick]

What 4 memory channel Haswells? AFAIK, the Pros are using Ivy Bridge-E based processors.

[Mark Rose]

Originally Posted by sdbardwick

What 4 memory channel Haswells? AFAIK, the Pros are using Ivy Bridge-E based processors.

You're correct. My apologies.

When the Haswell-based Xeon's come out, then it will matter. But that's not until next year.

[Yuno]

28.1 with my ivy bridge runs so slowly & the fft lengths only last 5 mins instead of the usual 15? it droops vcore to the same amount and gets to the same temps as 27.9 & loves to crash. is it trying to force haswell instructions onto a cpu that doesnt have them or is it full of bugs or what? 27.9 goes flying & completes tons of tests..

[Prime95]

Originally Posted by Yuno

28.1 with my ivy bridge runs so slowly & the fft lengths only last 5 mins instead of the usual 15? it droops vcore to the same amount and gets to the same temps as 27.9 & loves to crash. is it trying to force haswell instructions onto a cpu that doesnt have them or is it full of bugs or what? 27.9 goes flying & completes tons of tests..

All is OK. In 28.1 I changed each torture test to run more iterations. The theory is that the time spent running iterations is more stressful than the time doing setup work.

Sorry about the loving to crash. It is either due to the increased stress or it could be due to a bug -- especially if the crash comes in the same spot every time.

[Yuno]

Originally Posted by Prime95

All is OK. In 28.1 I changed each torture test to run more iterations. The theory is that the time spent running iterations is more stressful than the time doing setup work.

Sorry about the loving to crash. It is either due to the increased stress or it could be due to a bug -- especially if the crash comes in the same spot every time.

it is most common at the 24k fft, it crashed once on stock speed too crash as in "prime95 has encountered an error etc" crash. i think small fft should default to 8k ~ 32k instead of 16k the caches of modern cpus have grown a lot, 24k is much more stressful than 8k or 16k.

[JTL]

Originally Posted by JTL

Is the difference between the mac OS X mprime v27.7 and prime 95 v27.9 only for the GUI of prime95?

Is the difference between the mac OS X mprime v27.7 and prime 95 v27.9 only for the GUI of prime95?

[Prime95]

Originally Posted by JTL

Is the difference between the mac OS X mprime v27.7 and prime 95 v27.9 only for the GUI of prime95?

Yes (and no). There were a few bug fixes between 27.7 and 27.9. These fixes are described in the second post of this thread. Unless you are running multi-threaded FFTs you shouldn't be affected.