Wont boot at 950 or 1 GHz didnt touch the voltage not sure how high to bring it up?? its working fine at 900 MHz right now at 1.5 vcore. took a couple cold boots to get it back to default. this Duron just blows away my celeron 2999 MIPS 1238 MFLOPS at 900 MHz that allmost doulbe what my 550 celeron did but really cant tell to much in real world a little.