H110 Pro BTC+ Cant boot(post) with more than 8 SAME GPU(13 mixed cards are fine)

Hi,

I used my H110 for a very long time with 13 mixed GPUS. Eventually, I bought a second H110 and 13 rx 5700 xt graphics cards. I thought everything will be the same straight forward, but I faced a very strange issue. My rig does not boot (post) if I add more than 8 the same model GPUS, i.e. once add 9 rx 5700 xt, click power button there is just nothing comes up.

For example,
8x rx 5700 xt = boots fine
8x rx 5700 xt + 3 rx 570 8gb = boots fine
9x rx 5700 xt = fails to boot

I did try all the suggestions in a similar topic
http://forum.asrock.com/forum_posts.asp?TID=6589&PN=2&title=h110-pro-btc-cannot-boot-with-more-than-9-gpu

added more rams
configured GPU as Parsec in the topic above suggested
my CPU supports 32 PCIe lanes
I did try changing all cables, risers
I have 3x850W power supplies which provides more than enough power for 9 gpu

Setup:
H110 pro BTC+
Intel G3930 CPU
4GB Ram
500GB Sata SSD
13x RX 5700 XT
3 x Corsair RM850X PSUs (850 Watts each).

Any ideas why the rig works perfectly fine and stable using 13 mixed cards or 8 same and 5 other brand cards, but it does not work once I add 9 same model cards?

Topic: H110 Pro BTC+ Cant boot(post) with more than 8 SAME GPU(13 mixed cards are fine) (Read 108 times)