The Gemini II has not received good reviews but no way should it be that bad.
Your vCore is not too high though you do not say how high you are running your chip. Either your heatsink is horribly concave or your mount is bad. Check and make sure that the mount is good and tight and all corners are equally tight. Hopefully, you have a back plate??
Sounds like a bad mount to me.
I've been having problems with my first OC build. I've reseated the heatsink and applied AS5 almost 6 times and I always get the same result:
Coretemp reports idle temps of 49degrees
Speedfan reports idle temps of 35 degrees
I ran Prime95 for 4 minutes then stopped b/c coretemp jumped to 80-90degrees while Speedfan went to 65-75 degrees.
my Vcore is 1.375 and i have 1.95volts going to my ram
here are my specs:
DDR2-1066 crucial ram
abit Ip35-E mobo
Gemin II heatsink w/ 2 120mm fans
Antec p180b case
Antec earthwatt 430 psu
Probably your heatsink not being flat. Some of them are pretty bad. With thermal grease on, try to remove the HS by pulling straight up. It shouldn't come off that easy. It should shift a little (there should be some suction). Also see if you can tilt it.
I'm thinking this is the problem...give it a try. I sanded mine on a glass top...it worked very nicely.
What stepping is your CPU? cpretemp .95 will read temps 15C too high on L2 stepping CPU's maybe others. It can use a Tj Max temp of 100C when it should be using 85C for its calculations. Therefore the +15C temps.
Also you need to be specific as to your load temp. Giving us a 10C window helps us not. Assuming the temp was correct. 65C is a fairly normal (barely warm) temp for a OC with substandard cooling. Whereas 75C is considered "HOT". Telling us your load temp is 65-75C tells us that you aare either running perfectly normal or your running too hot.
I have G0 stepping
When my cpu is running the torture test, the TJunction temps (max 100C) jump from ~46 to ~low80s. I'm pretty sure this isn't normal. I don't understand why it jumps so drastically.
btw, temps are measured using Core Temp 0.95.4
Further speculation isn't necessary. If you just read the Guide and work through the Calibrations section, then you'll know what your temps actually are, and that they're accurate. Once this is known, you can eliminate variables and identify any remaining temperature issues such as a concave IHS and / or HSF.