Windows 7: Why varying times for a Backup?

I have an i7 870 processor on a GA-P55A-UD7 motherboard running Win 7 64bit.



I backup (system image) about once a week to two different drives, both internal drives. I have an SSD for a system drive.

Generally my system images take 4 minutes. Every now and then they may take 7, 9 or 11 minutes.

Take this morning, I imaged to F: and it took 4 minutes. Immediately after this I imaged to G: and it took 7 minutes. F: and G: are identical 750Gb WD drives on same SATA interfaces. Another day it will take 9 minutes and 4 minutes.

Nothing else is running, no Skype, no browsers, nothing apart from internal Windows functions.

I would have thought, two images one after the other should take the approximately the same time each?

More often than not, it will take 4 minutes but why, every now and then, maybe on the same session, does the odd one take twice as long, sometimes 3 times as long?

It is really bugging me

The first image may have created temporary files. If you do the 2nd image without removing the temp files created by the first, they will also get imaged adding to the image time.

I NEVER remove ANY workfiles between images. Never have, never will

Plus I ALWAYS log the run time and size of the main image files and they were both 30.5Gb so I'm afraid your suggestion isn't the answer

Also plus I have, many times, done two 4 minute images one after the other....

The OS is doing something in the background.
No idea what, but you might try looking at task manager processes or similar to find out.
Time the fast one for approx gb per minute, then when you see the second lagging behind that pace, investigate processes.
Of course it might be one of the the imaging processes itself causing the lag.
Who knows what Win 7 imaging is up to? In my view its incremental approach is much too complex.
For example, taking that first image changes all the various info Win is keeping to
stay current with the imaging. Then taking a second image changes that again.
No idea what kind of indexing/houskeeping is taking place, or at what frequency.
That's really the nature of "hot" imaging, and the main reason I always do cold imaging/restoring.
I've used both the Win 7 imaging and Ghost 15 to make consecutive backups to identical drives, as you do, and they are always within a few seconds of each other in time consumed.
Difference is I only image cold.

My guess would be that there is contention from disk activity. Whilst you are imaging, look at the Resource Manager > Disk tab and see whether you can determine any major differences from run to run. If you see processes that create a lot of disk activity and are not directly related to the imaging activity, note the names of those processes. Then we'll go from there.

How do you "cold image" with Backup & Restore? I used to backup from DOS with old old Ghost but not for a long time. I use B & R as it gets the "offset" correct when I restore my SSD.

I don't know if this is still an issue but when SSDs first came out most programs had a problem restoring SSDs which is why I stick to B & R

I only do consecutive images not concurrent.

Just out of curiousity I reversed the sequence this morning. As usual NOTHING except Windows internal functions running. G:, first this time, still took 7 minutes and F:, second this time, still took 4 minutes.

Did I make it clear that F: and G: are identical drives with identical contents? I already have 3 RAID 0 mirrors so I manually synchronize F: and G:

It was all clear, except for RAID, and now you've identified that it's one drive taking longer, no matter the sequence. I know nothing about raid, and how that might
interreact with B & R.
To do it cold, create a system repair disc. It's an option on the B &R screen.
I don't know anything else.