I generated deltas for the last 20 updates on my system. The total delta size is 12M, while the total package size is 73M. So the overall ratio is pretty good imo. Afaik, only one delta on the 20 didn't reach the 0.7 ratio : attr The ghostscript one is unbelievable : 5,7K vs 29M ! Here are the packages, deltas and their size : 56K attr-2.4.41-1_to_2.4.43-1-x86_64.delta 79K attr-2.4.43-1-x86_64.pkg.tar.gz 3,6K crda-0.9.5-2_to_1.0.1-1-x86_64.delta 13K crda-1.0.1-1-x86_64.pkg.tar.gz 254K curl-7.19.3-1_to_7.19.4-1-x86_64.delta 555K curl-7.19.4-1-x86_64.pkg.tar.gz 444K e2fsprogs-1.41.3-2_to_1.41.4-1-x86_64.delta 1,3M e2fsprogs-1.41.4-1-x86_64.pkg.tar.gz 5,7K ghostscript-8.64-2_to_8.64-3-x86_64.delta 29M ghostscript-8.64-3-x86_64.pkg.tar.gz 2,5M git-1.6.1.3-1_to_1.6.2-1-x86_64.delta 6,4M git-1.6.2-1-x86_64.pkg.tar.gz 39K hdparm-9.10-1_to_9.12-1-x86_64.delta 56K hdparm-9.12-1-x86_64.pkg.tar.gz 6,1K iw-0.9.8-1_to_0.9.9-1-x86_64.delta 15K iw-0.9.9-1-x86_64.pkg.tar.gz 369K kbd-1.14.1.20080309-2_to_1.15-1-x86_64.delta 1013K kbd-1.15-1-x86_64.pkg.tar.gz 569 libmad-0.15.1b-3_to_0.15.1b-4-x86_64.delta 132K libmad-0.15.1b-4-x86_64.pkg.tar.gz 89K libsndfile-1.0.18-1_to_1.0.19-1-x86_64.delta 423K libsndfile-1.0.19-1-x86_64.pkg.tar.gz 17K libv4l-0.5.7-1_to_0.5.8-1-x86_64.delta 56K libv4l-0.5.8-1-x86_64.pkg.tar.gz 79K libxi-1.1.4-2-x86_64.pkg.tar.gz 47K libxi-1.2.0-1_to_1.1.4-2-x86_64.delta 4,1K man-db-2.5.4-1_to_2.5.4-2-x86_64.delta 959K man-db-2.5.4-2-x86_64.pkg.tar.gz 1,2M man-pages-3.18-1_to_3.19-1-x86_64.delta 4,4M man-pages-3.19-1-x86_64.pkg.tar.gz 1,5M ncurses-5.7-2.1-x86_64.pkg.tar.gz 263K ncurses-5.7-2_to_5.7-2.1-x86_64.delta 951K nvidia-180.22-1_to_180.29-3-x86_64.delta 2,6M nvidia-180.29-3-x86_64.pkg.tar.gz 6,1M nvidia-utils-180.22-1_to_180.29-3-x86_64.delta 11M nvidia-utils-180.29-3-x86_64.pkg.tar.gz 1,2K pm-utils-1.2.4-1_to_1.2.4-3-x86_64.delta 39K pm-utils-1.2.4-3-x86_64.pkg.tar.gz 5,6K run-parts-2.30-1_to_2.31-1-x86_64.delta 8,9K run-parts-2.31-1-x86_64.pkg.tar.gz