What’s new with WinRAR 5.x? – Part 1

Categories: Advanced, RAR, RAR & WinRAR History, WinRAR | Posted on Nov 26, 2013

WinRAR 5.0 was released in September 2013. For many of us it’s most significant change is the ability to now create RAR5 files. These have a higher compression ratio and feature significant speed gains compared to compressed files created with WinRAR 4.x.

The earlier RAR and ZIP compression options are of course still available to us with WinRAR 5.x, to maintain compatibility for users who have not yet updated to this new improved RAR5 standard. You may need to remember this if you are about to upload a .rar file for others to use, or before email it to someone who may not have updated yet.

To do this you do need to make sure that you select the RAR option instead of the newer RAR5 option, as shown here:RAR Option
A much better long term solution would be to advise them to update to the latest version as downloading and installing WinRAR 5.x is very easy.  They just need to go to www.winrar.co.nz/download-winrar and select either the 64-bit or 32-bit version to suit their version of Windows. Oh, you haven’t updated yet either? Then it’s even easier for you, when you have finished reading the rest of this blog then right click on the Join Us! tab above to go directly to that downloads page on my sales & downloads site.

How does WinRAR manage even better compression? The new RAR5 archive format implements an assortment of advanced algorithms along with the addition of further optimization that is specifically designed for modern software and hardware configurations. To put the comparison quite simply, there is no better option for file compression than RAR5.

The RAR5 algorithm has been upgraded from 128-bit AES standard to include 256-bit AES encryption – further ensuring that your data is fully protected. With RAR5 encryption, you can sleep well knowing your encrypted data is safe and sound, so lets take a closer look at these changes.

Compression ratio improvements
RAR archives have always provided a higher compression ratio than any competition. Now that WinRAR can create larger dictionaries of up to 1 GB with the 64-bit version of WinRAR 5.0, this leads to an even higher compression ratio than with the previous versions.

At this point you may be asking ‘What has a dictionary to do with WinRAR?’
The short answer is it’s the index to the compression code. What I mean by this is that WinRAR must very quickly analyse all the files you have selected to compress, looking for repeating patterns. These may be spaces, words, groups of characters or even patches of the same colour in a photo or video. Indexing such patterns allocates a short code for each unique pattern, so that the end result in the .rar file is a continuous stream of data with a unique short code in place of each repeat item, so that the result is a very much shorter file than the original. Then, usually at the end of the .rar file (or files), WinRAR inserts the Dictionary index for that set of codes which is then available to reverse the process to decompress all your data back to make an identical copy of the original.

So what this means is that when you need to compress larger sizes or numbers of files, WinRAR requires access to plenty of your computers ‘working’ RAM (memory), to parse (read) as many files as possible at a time, and to have sufficient space allocated for building the dictionary. As modern 64-bit computers usually have 4 or more GB of memory that now makes it possible to have up to 1 GB of it allocated for WinRAR5 to hold the your data dictionary as it is being built. For WinRAR 32-bit the maximum dictionary size has been increased up to a maximum of 256MB, with a default size for both WinRAR 5.x versions is now 32MB.
It’s easy to check this out for yourself, here is a screen shot with WinRAR5 selected and showing the default of 32 MB highlighted, and the maximum of 1024 MB (1 GB).RAR5 Otion


Compare this with the RAR option as shown in the first screen shot to see the enormous difference!
And while you have that window open check out the poor ZIP defaults and maximum Dictionary sizes.
You can now begin to see why the end result with WinRAR 5.x is a higher compression ratio in much less time, than was possible with WinRAR 4.x’s 4MB dictionary. If you are not yet convinced then how about testing each method for yourself with a large quantity of files!

By the way, in case you are wondering, both 32-bit and 64-bit versions of WinRAR 5.x can unpack archives with any dictionary size up to 1GB. The reason for this is that nowhere near as much RAM and computer resources are needed for unpacking an archive is required, compared to originally compressing as that is the most time consuming, complex and memory hungry function. It’s always much easier to reverse the dictionary process than it is to create it from scratch.

To be continued …

Join the Forum discussion on this post