The four turnovers led to 24 points for the Gamecocks, who improved to 4-2 overall and 2-2 in the SEC. Arkansas is 2-3, 0-2.
South Carolina quarterback Jake Bentley threw three touchdown passes while completing 16 of 31 pass attempts for 199 yards. Rico Dowdle led the Gamecocks on the ground with 61 yards on 11 carries.
Bentley's two touchdown passes in the second quarter -- a 62-yard connection with tight end Hayden Hurst and 18-yard strike to wideout Bryan Edwards -- helped the Gamecocks take a 17-10 lead at halftime.
Arkansas starting quarterback Austin Allen, who completed 12 of 24 pass attempts for 84 yards before being replaced by Cole Kelley in the fourth quarter, had a 5-yard touchdown completion to Jordan Jones in the first half.
The Razorbacks could not muster production with Allen in the second half and were adversely affected by turnovers on consecutive possessions in the third quarter.
Allen threw an interception that was returned 34 yards for a touchdown by South Carolina linebacker Skai Moore with 8:33 left in the third quarter, increasing the Gamecocks' lead to 27-10. It was Moore's 13th career interception, one shy of Bo Davies' school record set from 1969 to 1971.
On Arkansas' next drive, after South Carolina safety Steven Montac had a fumble return for an apparent score called back, Gamecocks linebacker T.J. Brunson grabbed another fumble and returned it 73 yards for a touchdown to make it 34-10.
South Carolina cornerback Keisean Nixon returned a Kelley interception 45 yards for a score with 3:33 left in the fourth quarter, putting the Gamecocks ahead 48-16.
An Arkansas fumble recovered at the Razorbacks' 15 in the first quarter by cornerback Chris Lammons resulted in a 33-yard field goal by South Carolina kicker Parker White.
After Kelley replaced Allen in the fourth quarter, the Razorbacks went 75 yards in 10 plays for a touchdown, capped by former South Carolina running back David Williams rushing for a 4-yard touchdown with 8:36 remaining to cut the lead to 41-16.
Before that drive, played mostly against South Carolina reserves, Arkansas had only 161 yards in total offense.
Kelley later engineered another scoring drive, culminating with a 34-yard touchdown pass to Jonathan Nance with 1:40 remaining. Kelley finished 8 of 13 pass attempts for 140 yards.