HD 4850 Memory Temperature?

So here's the deal. I noticed my HD 4850 with it's stock cooler is getting over 110 degrees C. So I was pretty sure it didn't used to get that hot, and decided to reset the heat sink. So I got that done, cleaned out all the dust, put new thermal paste on and everything, put it back together and shoved it back in the PC. Under load, the core temps are about 10 degrees lower, but the GPU memory temperatures are getting up to 105-110C now. I'm not certain of what they used to be before, but I'm pretty sure they were lower than this. Also, when I tried playing Mirror's Edge a bit later, it froze randomly about every 5-10 minutes, and I had to alt-tab out and back into it to get it going again. Also, around a half hour in, a greenish hue started appearing on all the surfaces. Neither of these things had ever happened to me before. I know enough about overclocking to know that is a very good indicator that the temps are too high, or the clock is unstable. So I quickly exited, and found the memory temps around 112C, with everything else around 98C. I am going to order an aftermarket cooler, but in the meantime, I want to verify that these memory temperatures are unsafe, and that they are probably what caused the unstable performance and graphics errors in Mirror's Edge. Thanks in advance.

Thats really really bad. What 4850 do you have? Link to it if you can. Also whats the case temp when its getting that hot? Mine doesnt hit 65 even under full load, granted it has an XFX cooler on it but still a 4850 should not be getting that hot.

I have the reference Visiontek card. I just ordered the Arctic S1 R2 cooler, along with the turbo addon, Scythe ramsinks, and another 120mm case fan. This should cool things down, unfortunately at the expense of $60