Thanks for the +rep, that is most kind of you SgtHawker
About your Matrix and i only ask because when i first bought mine i did this....is the 100% fan button pressed? LOL, i know it sounds silly but these dcll coolers are so quiet compaired to what one would expect that its easy to overlook. I ran my Matrix 100% the first week, i didnt know, software could not change fan speed and i was about to rma the card also. Even if the button is not lit up red press it just the same as the led light below may be defective.
The second suggestion for the fan issue (because this also happened to me) is that if the wire from the gpu fans to the pcb is not pressed fully into the receptical on the pcb then you may have issues with the fan speeds. One fan can be controlled while the other cant....or both cant be controlled. That wire will look like its pressed in all the way and it does not make a click sound ether, press on it anyways with your fingernail just to double check.
I hope your not going to have to rma that card. It was mentioned on the rog forums that there are very few cards left for sale and they just have their remaining stock held for rma purposes.
The mod works well for the Matrix cards as the Matrix has no retail waterblocks for them being they are nonreferance custom pcb. When your/if your going to do the mod and need any help feel just come here and ask any questions you have. Retaining the shroud can be difficult with this card but another user here (williampv) also did his matrix card and used a different method than i did so youll get to pick which one you like....or find another way lol.
Thanks again SgtHawker, glad you liked the mod