Nice research OP ::*)
Dual GPU & Core P5 case using the GPU plate & various cables= no go with the cables provided by TK & ordering another cable from Amazon TK store.
Original posted in the TK forums regarding the riser cable issues. If you have an issue with the cable provided post in this thread & they will send you a replacement, a shorty cable for single GPU.
Two more cables, one from Amazon & one replaced by TK. Both work unless the bend gets too tight at either end, the female or male ends of the riser cable. The riser cable should be longer like the original one that was packed taco style at 8 3/4". The replacement cables offered by Amazon or TK are not long enough if one is trying to utilize more than one GPU & provide the proper bend radius of the male cable to the MB PCIe slot or female PCIe adapter bottom end of the cable.
The riser cables should be 8 3/4" or longer so it is able to provide enough distance so a nice curved bend at the base of the PCIe connector & where the cable fits into the PCIe slot on the mainboard are possible.
Different bends, curved, tight while trying to get the largest bend on the cabled end of the PCIe slot & PCIe slot located on the mainboard.
If there is minimal bend on the cable where it is connected to the PCIe slot my computer will not boot. If I produce a nice bend relieving stress upon the contacts that connect to the PCIe cable & slot I can boot into windows, but not for long as opening a browser or word document will black out the screen. The more bend the longer I am able to stay working in windows opening programs.
Since I am working with two cables of different lengths, sizes 8 3/4" original cable & the 7 3/4" from Amazon & TK I am unable to get the proper less constrictive bends to utilize the GPU mounting plate. I would like to be able to use the GPU mount plate since my GPUs have rather large heatsinks, three fans & produce very noticeable GPU mounted droop.
Buy 3M expensive riser cables http://www.digikey.com/product-detail/en/3m/8KC3-0726-0250/3M12028-ND/3641402
or TK provides it's customers that are using more than one GPU with the option of purchasing a non taco cable that is 8 3/4" or longer. The cables TK sells on Amazon & on there website are not long enough for users of more than one GPU.
Please chime in if you are a user of the P5 & are using more than one GPU and utilizing the GPU plate with riser cables.
These finding have not been approved by the FDA, FCC, NSA, NASA, AMA, IAEA, ISIS, EPA, CIA, FBI, Kenneth Copeland, Joel Osteen, Ken Ham or Marianas Web.
::*)Edited by broken pixel - 4/7/16 at 9:34pm