240mm vs 280mm

I have just replaced my Thermaltake 3.0 Extreme 240mm radiator with the Corsair H110 280mm radiator.
I ran the same stress tests with same over clocking settings and I have worse performance! With the 240mm my CPU wouldn't pass 85 C but with the 280mm it hit 100 C!
I was using the 240mm radiator with two Corsair SP120 fans in push configuration.
The 280mm radiator is set up as push AND pull with corsair stock 140mm fans.
Could it be just the difference in the fans? This is really disappointing.

Fans or the mount of the block or the thermal paste application...

Nothing wrong with the mount, thermal paste is the preapplied one that came with the cooler, both on the 240mm and on the 280mm, so I guess I'll get some Noctuas A14 PWM fans. Or is there anything better?

Wipe that stuff off and apply new.

Those two rads should perform similarly for the most part if the 280 isn't better with the slightly larger cooling area and push pull fan setup.

Somethiig is wrong. Be it the mount, pump, thermal paste application something. That value is waaaaay too high.

Yup, Earth is right. As Earth said those both should perform similarly. Something else is wrong here. Pump dead, contact etc. Make sure everything is working than remount with a 3rd party paste. MX-4 is what I use for example.