Hey guys, I have a tb85 am trying to get 6 gpu going on but every time I populate the x16 slot with riser the others are not seen. I KNOW it is something stupid in bios I am overlooking, but have been trying for a couple days now so would appreciate a little pointer. Thanks!
Are you on Windows 10? If so, I built 2 6x470s on that Mobo recently so might be able to help. Firstly, if you're trying it on Windows 7, I highly recommend the still free upgrade to W10. I tried to build a few 6x rigs with W7 and was never able to get them running smoothly (or at all) with 5-6 GPUs... even after the reg-mod, etc. Once I went to W10, absolutely NO issues with 6, except of course for the crappy updates that can't all be stopped, but I think I have mitigated that aspect for now anyway.
One thing that I have found works best is to install the 1st GPU (via riser) in that x16 slot. I have done this on both TB85 rigs as well as ASRock BTC R2 and it worked perfectly. Originally, I tried other slots first and it tended to cause problems. I load the the first GPU to that x16 slot and have the monitor hooked up to it as well on all 4 of my rigs. After the x16 slot, I do the first (farthest right, closet to the CPU) x1 slot, then slot 3, 4, 5 & 6 in order, one at a time.
If this doesn't work, you might want to try different risers (if you haven't already). Seems like there are a few bad batches of the molex version powered USB risers going around lately as I have like a 50% fail rate on those lately and returned most of them. Luckily, the 6-pin PCIe versions seem to me much more stable... I am 12 for 12 on those so far.
Did you do any tinkering with UEFI (is it a UEFI install of Windows on a GPT partition?) and did you mess with PCIE version settings? I'm on 3 with my TB85 and want to add #4 and #5, right now not running UEFI boot. Thanks in advance!