Check Clemson and SCSU web sites as well as other land grant university web sites in states with hot humid climates for advice in local building problems. They publish lots of research and bulletins. My memory is that radiant barriers were popular for a time, but have become less so. The concept has merit. It is impossible to pull enough air through an attic and have much effect because most of the heat gain in the house ceiling is heat from the hot roof deck re-radiated to the other surfaces in the attic. Radiant barriers, theoretically, help with this. I think that what caused them to go out of favor is that they get dirty very quickly and that makes them ineffective. You should, however, confirm this with unbiased sources.

If you need a new roof, consider a cool metal roof. Consider hiring a home energy rater (BPI or Resnet) to identify low-hanging fruit for energy (and comfort) improvements. Often, there are local government or utility programs to pay for the evaluation or discount the cost. They know local problems and solutions appropriate for your climate.

It is my opinion that you should focus on good attic ventilation first. The ventilation you choose should be 'natural' ventilation and NOT powered.

This starts with vents along soffits of the home all the way around the eaves of the home that are not blocked and have unfettered access to the main attic. From there a few whirly birds and ridge vents do the rest so the heat can escape and new cooler out door air vents into the attic to replace the hot air that is leaving thru the ridge vents and whirly birds.

Attic insulation should be addressed at the same time.

oh wow. I think the previous owner had a company come in and use a spray paint gun to paint the house.. and i remember they painted the soffits on the first floor. i will look today and see if the second story attic soffits looks painted too. could that be a BIG issue, or is insulation going to help more ? I would fix the soffits either way, im just trying to understand the importance of the soffits and how they rank in determining the reason for my excess heat.

Attic venting is sometimes more about moisture than heat. The roof, including roofing material, and deck, ventilation method, insulation, and vapor barrier need to be considered as a system. The configuration needs to be climate appropriate. Before mechanical cooling, things were simpler. After that was added, constrution did not adapt very quickly at all and we are stuck with a lot of outmoded methods. Cooling in hot, humid environments added condensation as a problem to be dealt with. Although some newer approaches are now proven, some flopped and sone more will. It is a lot to sort out.

As Austin Air stated,it's very important ample air enter at soffit. Replace the screens if clogged with paint. Let the sources posted by ionized help you with this.