Working down from each teams highest rated victories to their worst and seeing which result is more impressive (rankings taken from Sagarin)

Best: Georgia def #20 Auburn 27-6; BYU def #39 Boise St 51-17
2nd: Georgia def #62 Kentucky 14-3; BYU def #56 Houston 43-26
3rd: Georgia def #65 Arkansas 37-10; BYU def #95 Louisiana Tech 45-14
4th: Georgia def #73 Tennessee 44-21; BYU def #100 Navy 55-3
5th: Georgia def #75 Miss St 31-24; BYU def #101 UTSA 27-20
6th: Georgia def #89 S. Carolina 45-16;BYU def #102 Troy 48-7

Worst: #8 Florida def Georgia 44-28; BYU def #205 N Alabama 66-14
2nd Worst: #1 Bama def Georgia 41-24; BYU def #119 Texas State 52-14

Looking at just that first list of 6 games, the teams should be very close.

I'd argue Georgia has the slight advantage in Best, 3rd and 5th, while BYU has the clear advantage in 2nd. 4th/6th are basically toss-ups.

Given all this, I'm prepared to say Georgia should be barely ahead of BYU (though it's hard to argue they should be separated by much either way). That said, a big win over #79 San Diego State could/should push BYU ahead (with Georgia playing #129 Vanderbilt)