For those who aren't familiar with GoodMerge, it is a tool that will take your ROM set and combine all version of one game into the same 7zip file, thereby compressing the file down to a fraction of what it would be if all version of the ROM were seperate. Usually the size of a single ROM. GoodMerge usually uses 7zip, and the resulting file sizes are impressive. For instance: 0094 - Akumajou Dracula - Aoitsuki no Juujika (J)(WRG).nds 0105 - Castlevania - Dawn of Sorrow (E)(Legacy).nds 0121 - Castlevania - Dawn of Sorrow (U)(Legacy).nds These three files are 192MB uncompressed. Using default ZIP compression gets them to about 23MB each, so about 69MB compressed. However, with whatever settings GoodMerge uses and with 7zip, it combines all three ROMs into a single 7zip file for about 17MB. That's 192MB compressed to 17MB. Now for my questions: I've been trying to figure out how to get the same results using 7zip without the GoodMerge tool, but I can only get it down to 50MB or so. It's not as simple as "just use the highest compression settings". How is it possible to achieve the same results manually? And is it possible to get close with RAR or ZIP?