In ALL tests the validation is included in the backups. Terabyte Image For Windows v1.64d + PHYLock System Partition = 10,850,520 KB (according properties of Window Explorer) 1. With compression.. : 7m42s (only compression = default) .IMG = 2,097,152 KB .001 = 2,097.152 KB .002 = ..837,001 KB TOTAL= 5,031,305 KB 2. No Compression.... : 8m27s .IMG = 2,097,152 KB .001 = 2,097,152 KB .002 = 2,097,152 KB .003 = 2,097,152 KB .004 = ..367,377 KB TOTAL= 8,755,985 KB 3. Acronis True Image : 7m29s (normal compression = default) .TIB = 5,140,539 KB The IFW-backup with compression AND validation byte-by-byte marked took 9m00s (unmarked = 7m42s) As you can see there isn't much difference in time and volumes between IFW and ATI. (I think that IFW does a much faster job for backup without compression.) ================================================================= This is a separate test for ATI with the 4 compression levels. How long does it take and how big are the volumes for each level ? Acronis True Image Home 9.0 Build 3677 System Partition = 10,848,780 KB (according properties of Window Explorer) 1. Normal Compression : 07m18s = 5,139,445 KB (default compression) 2. High Compression.. : 07m32s = 4,529,790 KB 3. Maximum Compression: 13m44s = 4,412,288 KB 4. No Compression.... : 14m54S = 8,756,949 KB Personally, I stick to the normal compression, the rest is useless.