Motherboards Maximus IV Extreme-Z PCI-E not working

Hello peeps,

As title suggests, trying to install some GPUs to the eponymous Asus motherboard, but not having much luck. I'm trying to put two 980 Tis into slots 1 and 3 as the motherboard suggests, but nothing shows up in 3. Nothing else is attached to the motherboard, slots 1 and 4 work, as do 2 and 4, but 1 and 3 refuse. Bizarrely, slot 3 with a single card also works.

Oddly, I did have a little poke at it when this issue happened before - think it might have been with two 670s - and I managed to get it to recognise them both. When I replaced them with the 980s, no dice. The internet is awash with people saying similar things, but they all seem to have added other cards etc. and apparently activated the NF200 switching chip, which appears to be the root cause. I have nothing else attached though.

So I suppose the questions are:

- what's causing this and what's the solution?
- failing a solution, does it matter really if I use x8 via Intel chipset on slot 1 coupled with x16 (supposedly) via NF200 on slot 4?
- or, is there any benefit to using x16/x16 via NF200 on slots 2 and 4?

This is driving me potty and as usual, the manual/Asus' website are underflowing with information, as far as I can make out.

Grateful for any (constructive) input!

 

Right - tried again yesterday with different slots/cards and it seems slot 3 is just dead (why?). Therefore, given that I have an ASRock Z77 Extreme knocking about, should I bang away with the Z68 Maximus on x8/"x16" (NF200) or just swap out for the Z77 ASRock? Any differences in chipset/features that are going to be a problem?

Answers on a post (card).

 

Yeah, BIOS at latest. I heard about the NF200 adding latency - is this likely to be noticeable with two 980 Tis? I'm fairly sure they can handle most things I play (not quite Pacman, but not exactly Crysis 7 either).

 

Ah, nice one - cheers bud. No advantage to switching the ASRock Z77 Extreme in then, I assume?