The blade you choose can make a huge difference. The only 28T blades I've used were real dogs....Vermont American and a nearly identical Skil blade. I'd strongly suggest picking up a good 24T ripper like a Freud Diablo D1024, Freud Industrial, Irwin Marples, CMT Industrial, DW Precision Trim, or Infinity. Keep the blade clean and sharp.
It'll also help a lot if the wood is flat and straight.
It'll also help a lot if the wood is flat and straight.