AlanHo Posted June 16, 2009 Share Posted June 16, 2009 Out of curiosity I did a check on the amount of rubbish claimed to have been removed by CCleaner versus the extra free space which appeared on my C: drive after it was run. Before....I ran CCleaner - windows explorer showed that the C: drive had 68,929,359,872 bytes of used space. After......I ran CCleaner - windows explorer showed that the C: drive had 68,767,039,488 bytes of used space. Hence reduction in space used on C: drive was................................................162,320,384 bytes of used space CCleaner reported that it had removed 22,070 MB from the C: drive. I ran CCleaner again and windows explorer now showed that the C: drive had 68,756,869,120 bytes of used space This was a further reduction of..................................................10,170,368 bytes of used space CCleaner reported that this time it removed 2.75 MB from the C: drive Can one of our experts please show me how you reconcile these figures. There appears to be a large difference in the space actually created on the hard drive compared with the amount claimed by CCleaner. Link to comment Share on other sites More sharing options...
pwillener Posted June 16, 2009 Share Posted June 16, 2009 I am also curious about that. It appears as if CCleaner reports far less than it actually frees up; could it have something to do with the phenomenon called "slack space"? (Slack space being the unused parts of the clusters that files occupy.) Link to comment Share on other sites More sharing options...
pwillener Posted June 16, 2009 Share Posted June 16, 2009 Alan, just to give some more thoughts about the "slack space" theory, do you know the cluster size of your C: drive? Link to comment Share on other sites More sharing options...
Moderators Augeas Posted June 16, 2009 Moderators Share Posted June 16, 2009 On the first run CC said it would remove 22 gb of data? I think that there's so much going on in Windows that it's impossible to do an accurate before and after count. For instance I've just run properties on the C drive, opened and closed CC, and run properties again. I now have 65k less free space. That's not a lot, but opening and closing CC isn't much either. What's used 65k, and will CC clean it later? Slack space is a good theory, I wish I'd thought of that. There's always the index.dat files, which are only deleted at boot time. I can't remember if they are included in the space removed figure. Well, to be honest I've never bothered about it before. Link to comment Share on other sites More sharing options...
pwillener Posted June 17, 2009 Share Posted June 17, 2009 There are always small fluctuations due to Windows and other services' I/O on the Windows install drive; the 65KB you mention may be typical. However, 22GB (CCleaner claim) vs. 155GB (actual freed space) is a huge difference - that is 700% of what was expected! I think Alan is right to be curious about this enormous difference. Link to comment Share on other sites More sharing options...
AlanHo Posted June 17, 2009 Author Share Posted June 17, 2009 Alan, just to give some more thoughts about the "slack space" theory, do you know the cluster size of your C: drive? I have no idea of the cluster size. I built the computer myself, loaded it with Vista Ultimate and let it format the new drives in NTFS default settings. I have just used explorer - right clicked for properties - but cannot see any info on cluster size. I have a second identical internal hard drive installed and formatted at the same time - I just used explorer - right clicked - "format" and note that it would have used an "allocation unit" size of 4096 bytes. I aborted the format of course and assume my C: drive is probably the same - but Windows will not let me use the format command because the OS resides there. My curiosity continues unabated. Link to comment Share on other sites More sharing options...
Moderators Augeas Posted June 17, 2009 Moderators Share Posted June 17, 2009 I think we can safely put money on the 22 gb being a false reading. It would be quite a feat to accumulate 22 gb of temp files, a third of the total data. NTFS cluster size default is 4k for both XP and Vista, I believe. Another complication is how disk space and data size is calculated. Is disk space the numbers of sectors times 512? And whilst a file may be reported as a certain size, when it is written to disk the data is coded and expanded by a significant amout (I've read figures of 6 to 13%). So 512 bytes of user data will not fit into 512 bytes of disk space. I think that CC reports the user data size of the files to be deleted, not the actual increased space they occupy on the disk. Link to comment Share on other sites More sharing options...
AlanHo Posted June 17, 2009 Author Share Posted June 17, 2009 The reference to 22 GB was a typo in Pat Willener's post - if you read my original post it says 22 MB. Link to comment Share on other sites More sharing options...
Moderators Augeas Posted June 17, 2009 Moderators Share Posted June 17, 2009 Yes, 22 gb is huge. I think we were both confused by the 22,070 MB, which in the UK (and Japan?) is 22 gb: 22 mb is more reasonable. Link to comment Share on other sites More sharing options...
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