I guess V7 would get you extended support given that V6 support will be ending in February, since that will be a year after V7 launched, but other than that it's unclear to me what V7 would offer you while you're on XP. The other major features of V7 are viBoot and now Macrium Image Guardian, but those aren't available on XP either viBoot requires at least Win8 (Pro or better, not Home), and MIG requires at least Win7.

Other than that, the only new behavior I remember that might affect performance is that V7 performs a one-time test of a disk using direct disk I/O and then file system buffering to see which is faster, and then uses that mode with that disk going forward - but V6 supports both methods too, so you could run that test manually and then stick with whatever is fastest anyway. The speed improvement of V7 is related to CBT, but that only applies if you capture multiple backups within a given Windows session and are using Differential or Incremental backups.and CBT isn't available on XP it requires at least Vista.

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