I have some big mobi ebooks converted by Calibre.The biggest one is about 15MB.When I was reading these big mobi files, I had often encountered the problem of kindle crash.When crashed, I had to do a hard reset

.I had not distinguished this is because of big file or the mobi file type.But I'm really sure the smaller mobi/pdf ebooks work fine.My kindle is kindle 4.I had saw that it has only 128M RAM.really?
Does anyone have the same problem?Thanks!