Originally Posted by LoRd_MuldeR
Any particular reason why LZMA2 is required?
AFAIK version 2 of LZMA is better suited for multi-threading, but actually gives worse compression than the original LZMA.
As NSIS installers only decompress and LZMA 1 already is damn fast at decompression, I don't see much use for LZMA 2 in NSIS...
(The only thing it could speed-up would be building the installer - at the cost of bigger installer size)
I played around with lzma vs lzma2 today a lot. There is no significant size difference between lzma and lzma2 on maximum compression settings - using 7zip 9.29 alpha (any other settings don't matter, because lzma2 is always faster - mx9 compresses faster to lzma2 on a quadcore, compared to mx3 on lzma). The version used in nsis actually compresses consistently worse to lzma, than 9.29 to lzma2 (tested by compressing with nsis, vs feeding nsis lzma2 mx9 already compressed files and switching compress of).
It would be really great to have lzma2 supported by Nsis and having Nsis move to up to date 7z version (nowadays speed matters much more than maybe 40-50KB increase in installer size due newest 7z - though I doubt it would make such a big difference).
Second thing in line of course would be great to have proper filesize >2GB support - too bad if this won't make it into Nsis 3 - whenever it appears...