0Google Earth: How to fix poor quality overlays

I’ve recently had some prob­lems with dis­play­ing large over­lays (gen­er­ated from NASA SRTM data) in Google Earth. Although the over­lay data I expor­ted was very detailed google earth was dis­play­ing a blurry mess which was imprac­tic­al for my inten­ded pur­pose. Search­ing around on the ‘net did­n’t reveal any­thing use­ful so as a last resort I tried switch­ing from “Dir­ect X” to “Open GL” mode (under tools: options).

Upon restart of the applic­a­tion the qual­ity of my over­lay was as it should be. Suc­cess! I am still unsure why Dir­ectX mode appears to be faulty, my only guess is that it is because I am using Win­dows 7 which includes Dir­ect X 11.