Do keep in mind that share value has a high random factor...how many miners are on, how long you've been in the pool, the share bonus you get at times, and just plain luck on how long the block took. It's quite possible you could have had the same results with different versions and different clocks.
What is a share? What is share value?
On ypool we use shares as a measurement for how much you contributed to the mining process. The longer you mine, the more shares you will receive. Additionally each share is associated with a different value, called the share value. Depending on how 'useful' the share was you will receive more value. At the end of each round your share value will be used to determine how many coins you have earned.
Since finding high value shares is based on luck we use a simple rule to improve fairness: Each share is valid accross several rounds (20 for FTC, 160 for XPM). When you start mining you will notice a 'ramp up' period in which your share value per round adds up. When you stop mining you will see the opposite effect. Because of this we recommend that you mine at least half a day before you draw any conclusions about your earnings.
You can see your share value for the current round under 'SHARES' at the top right corner. When a block is found the round ends and the value is reset to zero. You can see a history of your share values per block on the personal stats page. Although be aware that the personal stats can be delayed by up to 20 minutes in rare cases.
All that said, until Archit releases his next version, with your 780 you should be running arCUDAminer.exe 1.0c, not any of the cmX versions or highper versions. They're bugged and actually reduce gpu load and even TDP drops 15% or more, a clear indication it's not working as hard (or it's super efficient, but the lower CPM gives lie to that idea)..