GTX460SE Overclocking

Ive Been An Experianced Hardware Expert For About 19 Years But There Are A Few Things I Am Not Sure About....

I Bought A GTX460SE At An Excellent Price ($129.00) It Is Identical To A GTX460 1GB In Everything But The Amount Of Shader Processors (288 vs. 384) Even The Stock Clocks And The RAM Type And Bus Are The Same (256-Bit DDR5) And It Comes Within 5% Or So In Performance In Realworld Processing Loads. However.....

I Am Upgrading My Main Panel From A Dell 2001FP To A Dell 2408FPW (From 1600x1200 To 1920x1200) Witch Im Sure Will Not Require Me To Run My Games At Any Lower Settings Than I Did At 1600x1200 But Id Still Like Some Extra Performance To Help Take Up Any Slack And I Doubt A New Card And Any Unessesary Spending Will Have Any Tangible Benefit, Thus The Following......

Im Currently Overclocked To 800MHz GPU/1600MHz Shaders/900MHz RAM And After Hours Of Gaming Or Intensive GPGPU (CUDA/OpenCL Etc.) Processong Shows No Instability And Rarely Gets Over 50C So I Know It Can Go Even Farther, So I Must Ask Out Of The Three Variables (Core/Shader/Memory) Witch Of Them Has The Most Impact On Overall Shader Performance?

This Will Help Me In The End Get The Most Out Of My GPU, Thank You.