Core/Shader Clocks

I have a GT 550m GPU in my Dell L702x laptop with 1GB DDR3 memory. I have a pretty high and stable overclock of 700/1400/950 on the core/shader/mem clocks, up from 475/950/900. I hit a snag where i get minor artifacting when i push the overclock any further in a few games and i was wondering if i take the 2:1 ratio off of the core and shader clocks if there will be any performance impact on my games. For example if i were to leave the core clock at 700 but increase shaders to 1450, would this have any negative effect? Thanks.