Same Graphics Card, different BIOS?

[CrowClaws]

Hi there,
I got a question about my Graphics cards. about two years ago I built a rig with one GTX 780 SC from EVGA, and about a year ago, I upgraded and got another 780 SC from EVGA. Now, I noticed that my old card is running about 10° hotter than the old one even tho its clock speed is slightly lower. I tried to improove that by getting rid of the dust in the card but it didnt really help, I guess the thermal compound just kinda broke down over the time. Just now however, I turned on GPU-Z and noticed that the cards got different BIOS versions, old card got 80.80.45.00.80 (P2083-0021), new card got 80.10.3A.00.80(P2083-0020). Now my question(s): How are the chances that the temperature increase are caused by a broken thermal compound after 2 years? And do the different BIOS versions affect the performance of the cards? I noticed the new card running on a higher clock speed, is that because it got a newer BIOS? If it does affect performance, can I upgrade my old cards BIOS? And if yes, how? 

 

Lots of thanks in advance for taking the time to read this and answer me!