ATLANTA — Georgia Tech and Georgia each started over on defense two years ago, hiring new coordinators to install 3-4 schemes.

As No. 13 Georgia prepares to visit No. 25 Georgia Tech on Saturday, defensive coordinator Todd Grantham’s Bulldogs boast one of the nation’s top-rated defenses. Georgia has held seven teams below 20 points in its nine-game winning streak.

Defensive improvement has come slower for Georgia Tech, which has held only two opponents — Maryland and Clemson — under 20 points. Coordinator Al Groh’s defense has given up more than 30 points in each of its last two games.

Georgia Tech coach Paul Johnson says the comparisons may not be fair. He says there’s more to examine than the two years in schemes with three down linemen and four linebackers.

“Well, I guess you can draw comparisons,” Johnson said. “You can compare whatever. It’d be hard to compare unless you play the same people, I think. That would be the only fair comparison. There’s different personnel and a lot of different things, I think.

“Coach Groh would be the first to tell you we’re not as far along as we’d like to be. But as I said at times we’ve played good enough to win eight games. It’s kind of been a mixed bag.”

Georgia ranks No. 4 in the nation in total defense and No. 2 — behind only Alabama — in run defense and third-down conversions.

Two additions have played key roles.

John Jenkins signed with Georgia from Gulf Coast Community College. Jenkins (6-3, 351) joined Kwame Geathers (6-6, 350) to give the Bulldogs a combined 700 pounds of run-stoppers at noseguard, a key spot in the 3-4.

“Getting Jenkins of course was big for us,” said Georgia coach Mark Richt. “He is a big space-eater at noseguard that you’ve got to have in this system.”

Jarvis Jones, a transfer from Southern Cal, became a force at outside linebacker. He is second in the nation with 12 1/2 sacks and leads the Southeastern Conference with 18 1/2 tackles for losses. David Pollack holds the Georgia record with 14 sacks in 2002.

Jones is one of six finalists for the Butkus Award given to the nation’s top linebacker.

Defensive end Abry Jones and outside linebacker Cornelius Washington each have 4 sacks.

Other key players include converted safety Alec Ogletree at middle linebacker and safety Bacarri Rambo, who has seven interceptions. Defensive backs Brandon Boykin and Branden Smith have combined for five interceptions.

Georgia’s improvement is obvious to Georgia Tech running back Roddy Jones.

“They’re a year older, a year more experienced, and they understand the defense better,” Jones said Tuesday. “And the guys they replaced, they replaced with really, really good players. (Jenkins) and the Jones kid playing outside linebacker for them, they’re really good.

“They’re big, they’re fast, they’re strong and it’s going to be a challenge for us.”

Georgia has forced 27 turnovers, the ninth-best total in the nation. Richt said his defense’s success on third downs and forced turnovers are the key indicators of the unit’s improvement from last year.

“Our defense has been effective at getting people off the field on third down,” he said. “A year ago, we were not very good at that at all. I can’t tell you how many times guys had third and long and made it. We’ve gotten some third down stops. That changes everything.

“Last year, people had some fairly long, sustained drives against us. We just couldn’t get off the field on third down. That one stat has made a big difference, along with the turnover ratio. The amount of takeaways we’re getting. Those two areas hit me the most.”

Grantham says his players have kept their focus and given consistent effort.

“It’s the next week, the next game,” Grantham said. “You either get better or you get worse and it’s an opportunity for us to get better and improve our defense so that’s what we’re going to do.

“You’re always going to coach them hard and expect and demand and confront guys and do those kind of things, but for the most part I think they’ve prepared pretty well and they’ve answered the bell when we’ve asked them to. I’ve been pretty pleased with their preparation.”

Linebacker Julian Burnett leads Georgia Tech with 103 tackles. Linebacker Jeremiah Attaochu has five sacks but his season may be remembered for a crucial personal foul late in the Yellow Jackets’ home loss to Virginia Tech.

Asked to summarize his defense, Johnson said, “Well I don’t know that the defense is any different than the team as a whole.

“I mean, it’s been up and down. Certainly we haven’t played with the kind of consistency that we’d like. I don’t know that you’re ever going to be satisfied until you’re holding people to no points or 10 points or something like that. It’s always a work in progress. I think we’ve played in spurts and we’ve done enough to win eight games. We’ll see if we can win some more.”