Does Winrar support multiple cores?

Caporegime
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When extracting files from archives I notice that CPU usage is really low, like 15-25%, does winrar not support multithreading for extraction?
 
Generally extraction is going to be disk limited rather than CPU limited, especially if the rar file is on the same disk as the target location.
 
CPU speed will come into play as you ramp up the level of compression you require/are extracting from.

From the horses mouth however:

Since Version 3.60, WinRAR is opimized for multi-processor systems.

Multithreaded version of RAR compression algorithm improvesthe compression speed on computers with several CPU, dual core CPU and processors with hyperthreading technology.

Multithreading is enabled by default, but you can disable it in "General" part of "Settings" dialog.


In the command line mode you can control multithreading with -mt switch. This switch is available in Windows version only.
 
The thing is it's not being hdd limited here, it's taking 6mins to extract 5.2GB of data.

The website just mentions compression, which is why I asked here.

On a HDD with an 80MB/s rate it should take less than half that time surely? Copy 4GB of data to ram ~ 50 secs, copy to hdd 50 secs, then copy 1.2gb to ram ~15 secs, then to hdd 15 secs, totalling 130 secs, as opposed to 360.
 
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Theoretical speeds are rarely what you get in practice.

If you are extracting from and to the same platter you can as good as half the speed. Additionaly that is theoretical sustained transfer, I am pretty sure an extraction process is a little bit burstier than you might expect.
 
Yeah you will never get theoretical max performance when archiving as isn't just a simple file copy.

One tip is to make sure you are extracting to a different drive (preferably the one with fastest write speed and least fragmentation). If your source and destination drive are the same then obviously this will be very inefficient due to it needing to read and write from a single drive.

The biggest gains from multithreading will come from compressing rather than decompressing anyway as the bottleneck is much more likely to be on the cpu.
 
It doesn't copy it all to ram, it copies it to a temp folder iirc

7zip seems quicker to extract, especially if you do it from one drive to another
 
Have your archive on a different disk than your temp disk as said above it extracts to a temp location and then
Moves it over


Anyone got any Ssd timings?


There is a compression benchmarker In the about menu
 
Isn't that incredibly inefficient though? It means reading and writing at the same time which significantly reduces throughput.
Yes but it works. WinRAR have taken a techical decision which gives the best compromise between performance and reliability.

If you want an extraction tool that uses RAM for temp space then go ahead and write one.
 
and surely unless you have over 6 gb of free ram,then the swap file would be needed anyway for a 5.2gb archive....probably 12 gig thinking about it...
 
and surely unless you have over 6 gb of free ram,then the swap file would be needed anyway for a 5.2gb archive....probably 12 gig thinking about it...

You could copy it in segments, say 100MB, 1s to copy to memory and then 1s to copy to hdd.
 
you could...my point is that a large 5gig + archive isn't going to uncompress that fast however you do it realistically....
 
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