With those temps. you are going to be creating yourself some problems. If you are overclocking you will definitely want to go with an aftermarket fan and heat sink. You will also probably want to use a good silver paste for memory and core on the GPU. You may also want to add some fans to the case and do all that you can to make sure cables are not restricting air flow. Using this setup, being you have good air flow through your case the card should see temps around 60 to 65 degrees Celsius under full load. Anything higher then 65 on the card you start to have a lot of lag and artifacts on your screen.