If you do a preset scan it will scan very very fast. Preset scan will scan the transponder list only that is stored in the S10.
If you do a blind scan it will be slow or slower. Blind scan will scan all possible frequencies/transponders that are out there and that will slow it down .
So which scan is better ?
It depends.
For example,,,,
If I do a preset scan on all channels on 97 w ku, I scan in 256 channels. Most are free and some are scrambled.
If I do a blind scan on all channels on 97 w ku , I scan in 387 channels. Most are free and some are scrambled.
On both kind of scans I get dopple channels and scrambled channels but mostly I get dopples on scrambled channels.
After deleting dopples and scrambled channels, the blind scan will get me more channels than the preset scan.
At least for 97w ku. And this sat is the only one I get dopple channels when scanning.
This sat has about 200 viewable channels, but I found new channels this way I did not know about it.
But if I scan 107w C , the blind scan will yield 2 channels less for some reason. And the 107 w C sat is the only one that will give me 2 channels less when using blind scan.
If your transponder data in your S10 is up to date , the fastest way to scan would be the preset scan.
It is best to blind scan even though it is slower. This way you will get transponder and channels that is not stored in your list.
Remember FTA channels are moving around and changing once in a while.