![winrar dictionary size winrar dictionary size](https://news-cdn.softpedia.com/images/fitted/340x180/how-to-pick-the-right-compression-settings-in-winrar.jpg)
The value N is the dictionary size (and the length of duplicates cannot exceed Fast Bytes).
#Winrar dictionary size archive
Usually, the dictionary is not stored in the archive - it is calculated upon the last N bytes of data to the current position (so-called sliding dictionary). The list of all duplicates (both actual data and their positions) is the dictionary. So it currently will mean that I can AND have better compression, AND have faster compression, using a larger dictionary size with fewer cores.įor LZ-based algorithms (Deflate, LZMA), the first step of compression is to find duplicate data and replace them with the links to the first occurrence. It's a strange phenomenon with Corei5/Corei7 and Core M machines of this time, until Intel fixes this issue. In this mode the CPU remains unthrottled until the temperatures reach too high.Īt 4 cores, the cpu does not enter turbo mode, because the speed is getting throttled due to cpu core heat. Tests have shown, that it is more beneficial for me to use 2 threads, instead of 4, as the cpu enters into turbo boost mode. That means that I can try to compress a file using 4 threads, or 2. It supports Intel Hyperthreading and Turbo Boost. If the uncompressed folder has several documents, or part of documents that are close to copies of one another (perhaps with a few bytes difference), doesn't 7z has to rebuild the dictionary in all 4 files while it can still use the same entries in the dictionary on the 2GB file?įor reasons of the above, I thought that the dictionary is more connected to the output file than the input file. Or choose to have 4x512MB files, with a 512MB dictionary. I can choose to create a 2GB file, with a 512MB dictionary,
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I have a 10GB directory, with a 512MB dictionary size (8GB of RAM, and 2 cores), and the compressed size is about 2GB.
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If so, what most likely would happen in this scenario?: So, if I get it correct, it would be most beneficial to have a similar dictionary size to uncompressed folder size? Doesn't 7z compress the dictionary data as well? I find it odd that the dictionary size is reflecting on uncompressed data.