I know my motherboard supports SLI, but the motherboard's two PCIE 3.0 slots are setup in which the two cards will be extremely close to each other. I'm just wondering if this is a cause for concern with the 660ti's. I've been searching around for a day or two now and haven't found anything specific on EVGA 660ti's and heating problems with this setup, but I'm just wanting to make sure before I go ahead and buy another one. I know these cards take in the air in the case while the exhaust goes out the back of the case, so would this be enough cooling for 2 cards right next to each other? Currently my 660ti superclocked runs ~70-75 degrees while playing far cry 3. Adding another card will still be in the safe range given the average 10 degree boost, right?
 
Also, any downsides to SLI? I've heard that the one major downside is that new games have to wait for driver updates, but Nvidia seems to be on the ball here.
 
Thanks for any and all feedback. This will be my first time doing an SLI setup so apologies if these questions are noobish.
 
-Auro
 
Edit: I posted a link to the motherboard, but it was taken down since I'm a new member. Hopefully you can search for it yourselves if need be.

Thank you malVizio for the reply.
 
I use a Corsair 500r case. From what I can tell it has plenty of airflow. It is starting to gather some dust on the front however.
 
The cards start to downthrottle over 70 degrees? I was unaware of this. I looked around in the NVidia control panel and couldn't find a way to manipulate the fan speeds, but I did watch the fan and temps while playing far cry 3. The GPU Load was ~99%, temps went up to 70-75 degrees, while the fan went from 30% to around 49-50%. Those numbers seemed fine to me, so please correct me if I'm wrong.
 
My PSU is about 4 years old. Again, I apologize for the lack of a link so I'll just put the name and model here: Xigmatek NRP-MC751. I'm pretty sure, even though it is old, my PSU will handle another card. I may need to buy a higher wattage PSU however, because I do plan on adding another HDD.
 
As for the motherboard, Duh! I was confused and was thinking the PCI slot was the PCIE. Ooops. I suppose I've been fretting over the air flow for no reason. Don't you love it when your mind plays tricks on you?!
 
Please let me know about my GPU and temps, and if the PSU should be replaced in your opinion. I don't have too much money to throw at a computer at the moment, so if I don't NEED to replace something I most likely will not.
 
Thanks for the continued help.
 
-Auro

After using the PSU Calculator, it looks as if I am in the clear. The calculator says I'm looking at 450W which seems a little low for a SLI setup, but I'm no expert.
 
I downloaded and installed EVGA Precision. Just ran Far Cry 3 for about 20 minutes. Card stayed around 68-69 degrees occasionally hitting 70. Interestingly enough, the clock speeds I got in game were 1149mhz and around 1098mhz while my boost clock is set at 1059mhz.  Don't know if that's an issue or not, seems to me that the card is more powerful than the specs on the box, which I'm not complaining. 
 
Seems that the card ran just fine in the 68-70 degree range. Temperature gauge wasn't anywhere near the top, so I should be in the clear, as far as the cards temperatures alone and with SLI, correct?
 
-Auro

i give also another tips...if you would like to record while gaming MSI Afterburner got same controll of Precision but give you also this possibility...
i find it very use full since it's free :D:D (but remember to remove Precision be4)

yeah msi afterburner got the possibility to record video!!
;D
glad i helped you!