GPU's running hotter after mainboard replacement...please help!

[soilworker]

Hello people,
as i said, my older mainboard got toasted, and it still was in waranty, so i replaced it with the same new model. After that, my two GPU's (Sapphire HD 7950) are running way hotter, about 79C° and fan speed of 85%. Before the replacement they worked stable at 71-72C° and fan speed of 65%. Im using the same cgminer setup as befor, the only new parts in the rig are a new powered risers, (i had standard risers before). I tried to put the standard risers back instead the powered ones, but the result was the same. I don't really have any clue, what causes the temp increasement. Please help if you have any suggestions!
Thanks in addvice!

[soilworker]

I forgot to mention, that i didnt really overclocked them a lot, they are running at 1050/1250 undervolted at 1087v. The stock core/mem is 925/1250. My mainboard is Asus M5A99X EVO R2.0.
PSU is Enermax Platinium Platimax 1000w.

[junk1]

My only theory would be that the defective MOBO did not feed the GPUs enough data or power, so they were throttling off 100% and were running cooler.
On my 6990s the current draw went up by like 40% after i added water blocks to them and so they stopped throttling back. in my case  they were throttling back b/c of temperature, in you case might be b/c of faulty MOBO. GPUs do get some of its electrical power from PCIe slot, so if mb could not give its full 150W spec for PCIe2 slot the gpu would work slower and run cooler...

[soilworker]

Thanks for your answer...the mainboard wasn't defective, it got fried because of me, so it worked stable, even the GPU's ran stable at 620kh each and 67-72°C. I have never had any hardware errors or dead GPU, and i only have 2 of them. As far as i know it is a problem with the power with 3 or more cards at one motherboard...so i dont think thats the case. I also red about it and a lot of people are running sapphire HD 7950 with the same hashrate at much lower temp as mine right now...normaly its about 65-70°C with the stock coolers, so my temps are pretty high right now...

[soilworker]

So i found out it was because of the powered risers, i put the normal ones and now everything works way cooler...about 10°C less heat...

[Camilio]

If your gpußs are not above 85°C there is no reason for drama otherwise I would would say the same as junk1. Try lowering the temp with extra fans.

What case are you using?