Since you're a locked multiplier you need to overclock by increasing the base clock.
By default your base clock is 200MHZ and your multiplier is 14x. Do the math, you get 2800Mhz.
So you'll need to increase the base clock to/ 250Mhz to reach 3.5Ghz.
The first thing you'll run into is your RAM speed. Before you increase your BCLK set the RAM to 1333Mhz, that way when you reach 250 on the BCLK you'll be back at 1666Mhz on the RAM.
Set your voltages to AUTO and your Loadline Calibration to Max. Once you boot up stable run Intel Burn Test or AMD Overdrive and watch your temperatures. You shouldn't exceed 60C. If you crash, you'll need to back down the overclock.
The other thing is you may need to set manual voltages, in this situation just keep working up the voltage on your CPU core until you're stable or too hot. You should not exceed 1.5V on the CPU.