I am going to be upgrading my GPU to a GTX 980 from a GTX 660 and while picking out what GPU I want, i don't know what the difference is between all of them.
For example,
http://www.newegg.com/Product/Product.aspx?Item=N82E16814132039&nm_mc=KNC-GoogleAdwords-PC&cm_mmc=KNC-GoogleAdwords-PC-_-pla-_-Desktop+Graphics+Cards-_-N82E16814132039&gclid=CjwKEAiA4rujBRDD7IG_wOPytXkSJACTMkgatTRpw6LPSeSfjw9vtO73uX0-LR2MQWINen93gIteVBoCJafw_wcB
http://www.newegg.com/Product/Product.aspx?Item=N82E16814487079&nm_mc=KNC-GoogleAdwords-PC&cm_mmc=KNC-GoogleAdwords-PC-_-pla-_-Desktop+Graphics+Cards-_-N82E16814487079&gclid=CjwKEAiA4rujBRDD7IG_wOPytXkSJACTMkgaI7DDBESCzWq6qVgocumrtiR4cNzt9NMgP4-YIft4thoC2qrw_wcB
http://www.newegg.com/Product/Product.aspx?Item=N82E16814127834&nm_mc=KNC-GoogleAdwords-PC&cm_mmc=KNC-GoogleAdwords-PC-_-pla-_-Desktop+Graphics+Cards-_-N82E16814127834&gclid=CjwKEAiA4rujBRDD7IG_wOPytXkSJACTMkgatBw0Zg4Kl_Xvpx7LWTtEo9x7W__Ym3khcNAnw6ModxoCOyHw_wcB
For example,
http://www.newegg.com/Product/Product.aspx?Item=N82E16814132039&nm_mc=KNC-GoogleAdwords-PC&cm_mmc=KNC-GoogleAdwords-PC-_-pla-_-Desktop+Graphics+Cards-_-N82E16814132039&gclid=CjwKEAiA4rujBRDD7IG_wOPytXkSJACTMkgatTRpw6LPSeSfjw9vtO73uX0-LR2MQWINen93gIteVBoCJafw_wcB
http://www.newegg.com/Product/Product.aspx?Item=N82E16814487079&nm_mc=KNC-GoogleAdwords-PC&cm_mmc=KNC-GoogleAdwords-PC-_-pla-_-Desktop+Graphics+Cards-_-N82E16814487079&gclid=CjwKEAiA4rujBRDD7IG_wOPytXkSJACTMkgaI7DDBESCzWq6qVgocumrtiR4cNzt9NMgP4-YIft4thoC2qrw_wcB
http://www.newegg.com/Product/Product.aspx?Item=N82E16814127834&nm_mc=KNC-GoogleAdwords-PC&cm_mmc=KNC-GoogleAdwords-PC-_-pla-_-Desktop+Graphics+Cards-_-N82E16814127834&gclid=CjwKEAiA4rujBRDD7IG_wOPytXkSJACTMkgatBw0Zg4Kl_Xvpx7LWTtEo9x7W__Ym3khcNAnw6ModxoCOyHw_wcB