Recommendations on new 2 x RTX 3090 setup

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If you want to use two 3090, you basically have the following options:

  1. Get a motherboard with four full-length pcie 16x (2-slot spacing). In such a way, you can install 2 3090FE with one slot separation between them, without interfering with the front-panel connections. Of course the upper card will suckle very hot air from the lower one. Don’t know if you’ll incur in thermal issues.

  2. Get any motherboard you like, and a case with 3-slot vertical mounting (e.g. the phanteks P600S), and a PCIe extension cable. This seems to be the most viable solution for 2 3090FE, as long as you have at least one centimetre of separation between the vertically mounted card and the side panel of the case. Note that you will lose the ability to use the NVlink bridge. Futhermore, since I expect the card to weigh a ton, it is not guaranteed that the bracket will handle the weight correctly. In such case, you will need a vga support bracket like this: https://www.amazon.com/upHere-Graphics-Anodized-Aerospace-Aluminum/dp/B079HSVSLR/ref=pd_lpo_147_t_0/134-1431875-3000427?_encoding=UTF8&pd_rd_i=B079HSVSLR&pd_rd_r=85c189a0-7cba-484b-aff0-126d28b80a05&pd_rd_w=tXiZI&pd_rd_wg=9Tjlb&pf_rd_p=7b36d496-f366-4631-94d3-61b87b52511b&pf_rd_r=HMZZ97NJ3HW5S1MNMTM0&psc=1&refRID=HMZZ97NJ3HW5S1MNMTM0

EDIT: None of the cases I have investigated do have the correct clearances for mounting at least one 3090 vertically.

  1. I really doubt there will be a 2-slot blower design for a 350W gpu, and a 3-slot blower seems to be unrealistic. The only remaining option are the liquid or hybrid models from EVGA.
    You can expect them to cost some 2000$. Also, Evga has not yet provided any ETA. https://www.evga.com/articles/01434/evga-geforce-rtx-30-series/
    I personally don’t like such contraptions. One adds other points of potential failure, the costs increase, and such cards are difficult to resell, mainly because people tend (understandably) to stay away from used liquid-cooled stuff.

My advice? Get two founder’s. Try to use it the canonical way. If the upper one overheats, buy a case with 3-slot vertical mounting option.

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