I took a DVD that I recorded a TV show on at full quality (1 hour– 4.2Gb worth of VOB’s) and I ripped it into one long mpeg-2 file. I then de-mux’d the file and converted the AC3 file (the audio) into one very large 32bit wav file (about 1.5Gb’s).

I imported it into Audacity on the 32bit Windows XP System and saved the file to an 128Kb/s mp3 file…16 mins. and 4 secs. later…

It whould be noted, that I used a couple of analytical programs that come with NT to monitor disk read/write and CPU usage while the test was running. The program/OS used virtual memory continually and only loaded a small portion of the input file into memory at one time. Interestly enough, Audacity or the OS did not use the four threads of the CPU very efficently sending most of the processes through only one or two of the threads at a time.

So to be fair again, I turned off virtual memory restarted the system and did the test agian.

13 mins. 15 secs. later...

Now time for the Linux 64bit System…Same 1.5Gb wav file, same version of Audacity (just ported to Linux)…

8 mins 1 sec. later…

Now I have to admit that since I am a relative noob to the Linux OS I couldn’t monitor it’s activity as well as I could in Windows. That of course has nothing to do with the abilities of the system and more to do with my knowledge of the tools available… Anybody wanna chim in with a comment that will point me to the tools in the Linux OS that can do all this (I know they got em!) Please do!

Suffice to say, with the tools I know about I could see that Audacity/the OS loaded about 20 times more of the original file into memory at a time compared to Windows 32Bit and that can’t be just because there is more visible on the 64bit system. Also, Linix never used it’s swap space and very rarely used the HD at all. Obviously it had to read from the input file and write out to a temp file and finally to the output file eventually. But while it was processing the little HD activity light barely blinked. While on the Windows System (virtual Memory enabled or not) the HD light was flickering continually. Later I loaded a 4.2Gb mpeg-2 into a couple of vedio editors in Linux and it did use it’s swap space. What percentage of RAM space vs input file size Linux uses to determine when to use swap is unknown to me… Please chim in if you know!

In Windows I think I read some where that its about 40%, ie. you got 4GB’s total, and 3GB available and you try to load a 4GB file into a program, the OS  will only use up to 40% of the available RAM before using virtual memory. Note: that’s 40% of RAM used by all the programs currently in RAM, yours and the systems!

Conclusion: