Winrar Extract Speeds Vary

[DasFox]

I'm downloading Star Trek episodes off of Usenet, and of course typical to Usenet are PAR files with the rars.

Well I noticed the other day that if I check the rar files with QuickPar first, then extract the rar files afterwards the speed of extraction is THREE TIMES FASTER!

So said the other way, without using QuickPar, running 'Extract' in Winrar, the extraction will run 3 times slower. I don't get this, what does running QuickPar have to do with making Winrar run the extraction process faster?

Below are screenshots that show the proof.

QuickPar running first:
http://img152.imageshack.us/my.php?image=screenxc7.jpg

Winrar running after the check with QuickPar:
http://img412.imageshack.us/my.php?image=screen2fs4.jpg

Winrar run alone without a check with QuickPar:
http://img396.imageshack.us/my.php?image=screen3eq8.jpg

This happens without fail 100% each, and every time I run this test.

Can anyone explain why this is?

THANKS

P.S. This test was done on two differenet size videos, that vary slightly, but this still happens the same when running on the same exact file.

 

[DaveSimmons]

Windows uses a huge part of memory as disk cache when you aren't running a memory-intensive app, so your second run is using a Ramdisk instead of the HD.

 

[DasFox]

Oh so Quickpar was running off the hard drive, then afterwards Winrar ran off memory? Whereas the first time I'd run Winrar ti would run off the hard drive, which is the reason for the slower speeds?

THANKS

 

[rainypickles]

DaveSimmons: so the complete rar files are cached in RAM?

pure speculation: looking at the pictures, the two files are being extracted to different drives. same drive, multiple partitions? maybe extracting to the same partition is faster (closer location) than different partitions? maybe the hard drive cached the files or file locations so when winrar does it, it's faster? i just think this is really interesting.

what happens when you unrar, delete, then unrar again? is it three times as slow, then fast again?

 

[jbritt1234]

Maybe restart before each test?

 

[Nothinman]

DaveSimmons: so the complete rar files are cached in RAM?

If he has enough memory, yes.

 

[DasFox]

Originally posted by: jbritt1234
Maybe restart before each test?

Restart?

I have 1GB