Well of course the ones to avid would be:
Reference card
EVGA SC series (basically same as above w/ better cooler since 5xx series)
Reviewer Ratings:
Worth looking at:
(9.8) - MSI GTX 1080 Ti Lightning Z 11 GB
https://www.techpowerup.com/reviews/MSI/GTX_1080_Ti_Lightning_Z/
(9.6) Zotac GeForce GTX 1080 Ti AMP! Extreme 11 GB
https://www.techpowerup.com/reviews/Gigabyte/GTX_1080_Ti_Xtreme_Gaming/
(9.9) Gigabyte Aorus GTX 1080 Ti Xtreme Gaming 11 GB
https://www.techpowerup.com/reviews/Gigabyte/GTX_1080_Ti_Xtreme_Gaming/
(9.7) MSI GTX 1080 Ti Gaming X 11 GB
https://www.techpowerup.com/reviews/MSI/GTX_1080_Ti_Gaming_X/
(9.7) ASUS GTX 1080 Ti Strix OC 11 GB
https://www.techpowerup.com/reviews/ASUS/GTX_1080_Ti_Strix_OC/
Best avoided:
(9.4) EVGA GTX 1080 Ti SC2 11 GB
https://www.techpowerup.com/reviews/EVGA/GTX_1080_Ti_SC2/
(9.4) Palit GeForce GTX 1080 Ti GameRock Premium 11 GB
https://www.techpowerup.com/reviews/Palit/GeForce_GTX_1080_Ti_GameRock_Premium/
(9.3) NVIDIA GeForce GTX 1080 Ti Founders Edition 11 GB
https://www.techpowerup.com/reviews/NVIDIA/GeForce_GTX_1080_Ti/
2. Max OC - What the card does out of the box is basically meaningless as its basically the number he bean counters are happy with based upon what % of cards they are willing to have returned because they can not remain stable at advertised speeds. With EVGA, have been there and done that. It's what it does when you have installed Afterburner that matters.... By order of fastest card
I don't know what to make of the reference card finishing so high even tho it was throttling, but the EVGA and Gigabyte land at the bottom of the heap. All following data from above links.
MSI GTX 1080 Ti Lightning Z 11 GB - 221.5 fps
NVIDIA GeForce GTX 1080 Ti Founders Edition 11 GB - 216.2
Palit GeForce GTX 1080 Ti GameRock Premium 11 GB - 215.1
MSI GTX 1080 Ti Gaming X 11 GB - 214.3
ASUS GTX 1080 Ti Strix OC 11 GB - 214.2
Zotac GeForce GTX 1080 Ti AMP! Extreme 11 GB - 213 fps
EVGA GTX 1080 Ti SC2 11 GB - 209.3
Gigabyte Aorus GTX 1080 Ti Xtreme Gaming 11 GB - 209.1
3 Power Peak gaming / Noise / Heat (Load w/ OC)
MSI GTX 1080 Ti Lightning Z 11 GB - 309 watts / 33 dbA / 67° C
NVIDIA GeForce GTX 1080 Ti Founders Edition 11 GB - 267 / 84°C/ 39 dBA
Palit GeForce GTX 1080 Ti GameRock Premium 11 GB - 315 / 75°C / 38 dBA
MSI GTX 1080 Ti Gaming X 11 GB - 305 / 72°C / 35 dBA
ASUS GTX 1080 Ti Strix OC 11 GB - 292 / 69°C 33 dBA
Zotac GeForce GTX 1080 Ti AMP! Extreme 11 GB - 318 watts / 69°C / 36 dBA
EVGA GTX 1080 Ti SC2 11 GB - 272 / 69°C / 37 dBA
Gigabyte Aorus GTX 1080 Ti Xtreme Gaming 11 GB - 266 / 71°C / 33 dBA
It would appear that the EVGA and Gigabyte Arorus are nerfed by their power handling ability.
Answer to question 1 - Again, highest clocks do **not** necessarily result in fastest fps/. The 4 cards that delivered the fastest fps in the OC test are:
MSI GTX 1080 Ti Lightning Z 11 GB
NVIDIA GeForce GTX 1080 Ti Founders Edition 11 GB
Palit GeForce GTX 1080 Ti GameRock Premium 11 GB
MSI GTX 1080 Ti Gaming X 11 GB
Answer to question 2 - Things I'd consider
a) Sound/ Noise and power consumption ... data above.
b) PCB Components ... The reference card and the EVGA SC series have historically only differed in respect to the cooler with VRMs and other componentry unchanged. Whenever ya see, "just by the cheapest one, they are all the same", go read this article. By the time ya get done reading pages 2 - 4 and see who invested money in PCB improvements and who cheaped out, you already know who finishes 1st and who will finish last.
https://www.bit-tech.net/reviews/tech/graphics/nvidia-geforce-gtx-970-review/2/
With Boost 3 however, nVidia has kinda nerfed the ability of those vendors who invest in custom PCBs to realize performance improvements that they would otherwise be capable of. However, while the spread is smaller, it's still there are we see a 12.4 fps difference between fastest (MSI) and slowest (Gigabyte) cards. However we have also seen another thing w/ Boost 3 and that is manufacturers are skimping on their performance lines thinking that "well, no sense spending the money because Boost 3 will shrink any improvements". We saw that with EVGAs SC and FTW lines with 10xx series as they cheaped out on both lines, failing to provide thermal pads on VRM and memory resulting in a product recall / issuance of thermal pad kits. The low power limit on the SC tells me that the VRM isn't capable of handling the 300+ watts that the faster cards can handle.
c) Tech Support - When selected for a job in tech support, TS101's 1st lesson of the day is "get the user off the phone, blame the other guy whenever possible." having MoBo and GFX card same manufacturer eliminates that tactic.
d) Ventilation - make sure that ya have 50% more case intake fans than exhaust fans. Inlet air filters reduce case fan efficiency by up to 30% when moderately clogged with dust. To maintain positive air pressure, if ya have 5 fans go w/ 3 intake 2 / exhaust at worse. While this is mainly touted as a dust issue, what is rarely mentioned is that that dust will be carried by hot exhaust air from ya GFX card and PSU.
e) Alternate cooling - Hybrids are a waste of time, money and effort. have yet to see a CLC that beats a comparably priced air cooler. Usually provided with extreme speed fans to get close to air coolers in thermal performance, when you select quiet models, the thermal performance suffers terribly. If ya attracted to the all in ones, then use an AIO assembled from **real** custom water loop components w/ 1+ gpm pumps, copper radiators such as the Swiftech H240 X2 (2 x 140mm) or H32 X2 (3 x 120mm).
Also hybrids cool the GPU only, sometimes leaving the memory and VRM lwith less cooling than the stock coolers. This can be OC limiting. Here's a 1080 Ti w/ preassembled, full cover EK water block which you can connect to the Swiftech units quite easily.
https://www.newegg.com/Product/Product.aspx?Item=N82E16814137144
Cost - The impact of cost, like noise, depends on the individual. If i can tell that my PC is on by using my ears ... well poppa ain't happy. For you, it doesn't matter. Cost is a similar item. In past years, folks would pay an extra $100 - $200 for Classified, Lightning and Matrix cards ... not today and the cost increase generally delivers too little return.
MSI GTX 1080 Ti Lightning Z 11 GB - Given limited availability, expect costs > $1,000
NVIDIA GeForce GTX 1080 Ti Founders Edition 11 GB - Not Recommended
Palit GeForce GTX 1080 Ti GameRock Premium 11 GB - Not Recommended
MSI GTX 1080 Ti Gaming X 11 GB - $755
ASUS GTX 1080 Ti Strix OC 11 GB - $795
Zotac GeForce GTX 1080 Ti AMP! Extreme 11 GB - $760
EVGA GTX 1080 Ti SC2 11 GB - Not Recommended
Gigabyte Aorus GTX 1080 Ti Xtreme Gaming 11 GB - $770
As far as what i see from the above....
If you had or were changing to a Swiftech All-in-One, I'd get the MSI 108 Ti Seahawk EK. There were 4 cards that beat the Strix, if only by a hair on last one ... but given the price advantage of $40 ... Id go with the MSI Gaming X