The critical temperature of the gtx 750 ti

Hello forumchane! Problems. I use gtx 750 ti from ASUS without extra power supply in conjunction with the i3. The fact is that in ordinary use temperature of the chip 57°, and under load of 95°. Still the fan never rose more than 88% of revs and noise strange, as if turbulence. Do you think it may be the fan cover or the thermal grease must be changed?