It's been quite some time after the previous release of Inkscape. I think the developer has made big changes while developing this version and the result is magnificent. Besides improvement on the functionality, they also improve memory management and fixing memory leaks on 0.46. Here's some proof from the Release Notes
In this version, Inkscape starts using the cairo library for rendering. It is now used for outline mode display which, thanks to using cairo and other optimizations, redraws faster by about 25%. More impressive are memory savings: thanks to cairo, in outline mode Inkscape now takes only about 50% of the memory used by 0.45 for the same file.
Exporting drawings with blur was particularly slow in 0.45; some files could take hours to export. Now this is fixed, in part by the faster algorithm mentioned above and in part by a bugfix in the export code. Now even the quite complex files with large blurs export at high resolution in at most a few minutes.