Yes it does sound like a Graphic card issue. I have a 4month old pc. With Nividia 9600GT 512mb. I have no issues but told others about emerald. They tried it on lesser cards like u have and had issues. They went back to SL viewer and do just fine. Maybe as some suggested trying SnowGlobe or another be the speed you need. But there is a non optimized Emerald to use also. I never tried it because never had to use it.