A head to head comparison of the 2008 Georgia General Election gives us an idea of the break down of the voters.    

John McCain received 2,048,744 (52%) votes beating Barack Obama who gained 1,844,137 (47%) by 204,607 votes in Georgia.

John McCain won 125 counties whereas Barack Obama won 34 counties in the total of the 159 counties in the State of Georgia.

Presidential General Elections

During the 2008 General elections, over 131M total number of votes were cast. Barack Obama got 69,448,278 (69.4 Million) over John McCain's 61,739,059 (61.7 Million). He won the popular vote by 7,709,219 (7.7 Million). Even though he lost to John McCain in the State of Georgia, his 1,844,137 gained votes represents 2.6% of his popular vote victory. The remaining 49 states contributed to the remaining 97.4% popular votes victory.

Top 15 Counties in Primary Elections vs General Elections

All Candidates (General Elections)

These 15 counties play an important role in these Primary elections. If a candidate, can get a sizable majority in the largest counties (Fulton, Dekalb, Cobb, Gwinnett), it becomes very difficult to win majorities in the smaller counties without voter outreach and increased voter participation in them. However, steady win margins in less popular counties can amount the marginal win to win the entire State. (As in the case of John McCain in the State of Georgia).

Top 15 Counties Comparison in Primary Elections vs General Elections

General Elections
Barack Obama

General Elections
John McCain

Fulton and Dekalb, two of the larger counties voted in favor of Barack Obama, giving him a 330K vote advantage. On the other hand, Cobb and Gwinnett, other larger counties, voted in favor of John McCain giving him a 59K voter advantage. However, steady marginal wins for John McCain in the less popular counties gave him an upper hand in the State of Georgia.

Related References: 2016 Georgia Primary Election Story, 2016 Georgia General Election Story, 2020 Georgia Primary Election Story, 2020 Georgia General Election Story, 2012 Georgia General Election Story