I want it for my sff build but slightly worried about temperatures. It's a small card and the 3090 generates a ton of heat.
Thoughts?

lol, its over 11" long. it might be "smaller" than the FTW3, but it's not a "small" card.
 
temps are fine.

worse comes to worse, you can buy a waterblock. it'll be expensive, but so would buying a FTW3 Ultra 3090.

Temps are gonna be fine on it. I wouldn't worry about anything. 

On the other hand, this guy has positive things to say about temps starting around 9 minutes:
https://www.youtube.com/watch?v=yq7ef7sKryg
 
So we have some conflicting reports.

This is my own opinion but personally I would not put an RTX 3080/RTX 3090 into any PC case that doesn't have optimal airflow. I have a 1000D chassis with two exhaust fans so I feel pretty confident about the airflow. 

If it doesnt work out you should have no problem selling it, so if thats the card u want go for it!

I picked up a 3080 XC3 Ultra from Alternate last week. But let's just say it was not a good idea for my Core 500 case. I think the cooling of this card will only really work in a very well ventilated case. There is a reason almost all cards are 3 slot.

rjohnson11
Agreed. You really need a good case with excellent airflow and you'll be fine. 

Luckily we are seeing a lot of good cases at reasonable prices now days but of course some are far better then others.

https://www.reddit.com/r/TEAMEVGA/comments/j3g150/xc3_meant_to_run_this_hot/
 
Not everyone seems to agree about XC3. Some with an optimized airflow can run 3080 / 3090 XC3 under or around low 70°C. I'd suggest to wait for XC3 depth reviews if we can get some. Jayztwocents got his 3080 XC3 around 72°C (same as FE btw) on open test bench with default fan curves. So if you bump up fan speed a bit, depending on your case of course... You might get good results. Or not. 
 
But I'll say that if you can afford a FTW3 without ruining yourself, depending on the price difference it might be worth it. I know i'm going for the FTW3 rather than the XC3 for my 3080. 

chumeniuk
I'm only going with a 3080 in my sff case.  Hopefully I can swap my 3080 FTW for either an XC3 or Tuff version.  After seeing how hot my 3090 FTW gets in a Phanteks Enthoo 719, I don't see it be feasible in a small case.

https://www.youtube.com/watch?v=96rmIYG1fp4
That's the TUF alright but FTW3 should be at least as good if not better. So... It shows that you can have a very small case but if done right, better result than a lot of people with a bigger case but that isn't optimized as well.

chumeniuk
 
I should have been more clear.  I was saying that a 3090 is not something I want to stuff into a sff case since it adds another 75+ watts of power to the mix.
 
As far as the card, the FTW3 is too big to fit in my case so I will need to swap it for something smaller in profile.

Oh, ok. I could find these measures :
XC3 :   28.54cm x 11.11cm x 4.51cm (2.2 slots)
TUF :   29.99cm x 12.69cm x 5.17cm (2.5 slots) 
FTW3 : 30.00cm x 13.67cm x 5.55cm (2.7 slots)
Strix :  31.85cm x 14.01cm x 5.78cm (2.75 slots)
 
If you want the smaller one, XC3 will be your choice against the FTW3 (1.5cm less length, 2.5cm less large and 1cm less height). But that'll depend on what you can fit and noise / temperature you're trying to get too. I feel like the TUF is running colder because (or at least while) it's running speeds at higher rpms than the XC3.
 
From what I could gather (so take it with grain of salt until someone do compare TUF vs XC3 / FTW3 on a review because so far that's not the case), XC3 runs at around 50 / 55 % fan speed at default, getting around 72°C. That should be around 1500rpm more or less. And when I look at this https://www.techpowerup.com/review/asus-geforce-rtx-3080-tuf-gaming-oc/31.html is seems that with the same rpm around (with quiet mode) TUF reaches the same temperature too. So it would seem the XC3 and the TUF are somewhat equal in cooling. Now, that is on open test bench so... Yeah. 

IWafflesI
3090 XC3 owner here. I was told I needed to try a different case fan setup so I bought a new case designed for optimal air flow and I still can’t get this card to stay under 80c unless I run the fans at 100%. Go for the FTW, which I plan to upgrade to.

I've been doing some digging and between your comments plus
 

EVGAfan587
I picked up a 3080 XC3 Ultra from Alternate last week. But let's just say it was not a good idea for my Core 500 case. I think the cooling of this card will only really work in a very well ventilated case. There is a reason almost all cards are 3 slot.

 
I'm just getting worried I might be in for trouble.  What does the community think?
 
I'm currently running the following.
 
Core 500 Case
ASUS ROG Strix X570-I(itx)
Tridentz 2 x 16gb @ 3600 16-16-16-36
3900x Cooled by a NH-U14S with Dual Push Pull... 
2080ti PNY 2080ti xlr8
800 Titantium SFX-L
 
I have a total of 5 fans (8 if you count the gpu) in that little case... But the end result is air is controlled and runs where you want it too.
 
I have 2 x NF-A12x25 taking air in from the top...
Just a 3-4 millimeters from the top intake fans, my Noctura 140mm 3000 rpm (Never gets past 1800rpm though) takes that direct fresh air and pushes it through the rad, and then the bottom fan pulls it from there and blows directly over my RAM with only ~2mm clearance.  Then I have a another 140mm rear fan blowing it all out the back of the case.
 
The Graphics card itself sits right next to the side ventilation pulling tons of fresh air directly into it and again blowing hot air out the back.
 
Up until now, I just love the entire system... Run's much cooler then my computer geek friend thought...
 
Under heavy FurMark stress testing
I couldn't get the GPU over 82.  CPU fully loaded 24 thread stress test tops out around 78
Memory tops out at 40
 
I should mention those numbers were taken in a very hot room on a hot summers day (6-8 degree's hotter then in my house).
 
Generally temps all around are much lower in my house, and I've reduced fan speeds even further. (doesn't sound like a Vacuum, although if I go turbo mode, yes it can sound a bit like a vacuum).
 
It's all a tight fit (literally mm clearance between everything), but it works thus far? (pics attached)
 
I've measured the clearance in my case and I figure at best I could fit a 2.4 slot gpu... maybe to play it safe 2.375... So I figure the 3090 xc3 ultra will be even closer to fresh clean air then the PNY 2080ti?
 
Am I in trouble? (starting to sweat a little).  I may need some help down the road undervolting?
 
 

brandobot
New xc3 3090 owner here. My temps are over 80 degrees C while playing CoD. The same case using a 1080ti barely tipped over 70 degrees C.

I've blasted my fans at 100%, tried opening the doors of my case and no difference in temps at all. This 2 slot heatsink is not enough for this massive card. There's a reason why most of these other cards have 3 slot designs. Was super excited to finally get my hands on the 3090, now i'm horribly disappointed at the performance.

The Asus Tuf at MSRP price runs at 67 degrees C under load...

Oh man, not looking good now is it....
 
I hoping undervolting can help, but I haven't toyed with that before... Erg.
 
(regardless when I get the card, I'll put it through it's paces and report back here on the forum somewhere.)