Installing a new GPU changed your CPU temperature? If you think thats the case check what your temperatures are with your old GPU installed. If the 65C you are referring to is instead of the temperature of the GPU thats a bit hot but still safe. GPUs run significantly hotter than CPUs. The 2600 XT is fairly low power, but if it has a weak cooler or is passively cooled it will still get up to reasonably high temperatures.
It's possible that your GPU is running hot and so is heating up the rest of the air in your case. This hot air then rises and may effect other components such as your CPU. What case are you using and how is the general airflow through your case? No component can ever be cooler than the air surrounding it andf the cooler that air is, the cooler each component will be.
I think there's some confusion here. Installing a GPU doesn't affect CPU temperatures. Everest test, I'm guessing you did stability? - this is meant to test CPU stability, so it hits high CPU temps. 65C is hot but fine and fairly normal with a stock CPU heat sink. If you want to truely test them out separately, use FurMark to test the GPU and Intel Burn Test or Prime95 to test the CPU and monitor temps. They are not related to eachother for the most part. As far as GPU temps go, 65C is fine.
EDIT: Well, what moody says is true if it's increaseing case temps it'll increasing CPU temps too, however, Everest isn't a very good one to use for stress testing. Test them separately.
Yes the temperature of CPU increases due to gpu. Gpu has a fan it's reflecting hot air onto the cpu I guess.. The case is next to a wall, when I give it more space for air circulation temperature does not get that high. (I cannot place it freely due to denseness in my room)
Maybe I should tear airing grids apart to allow more air circulation