New mobo, dead cpu?

Your post might get some more responses if you specified your hardware (motherboard type,specific CPU,video card,memory,Power supply type etc).
From what you mentioned none of us here knows if your CPU will work with your motherboard if you don't specify the above.
Once you do this other people on this forum might help you out.

Ah sorry about that.

I was running:

Asus P5K-E Wifi
MSI 8800GT
8600GT (for 3rd monitor)
Q6600 G0
Corsair 520W
4x1GB OCZ Special Ops Urban

Upgrading the mobo, gpu and PSU to:
Gigabyte x48-DQ6
2x Sapphire 4870x2
Ultra x3 1000w (still not arrived yet)

Though I was testing the rig initially with just the single 4870x2 then a 8800gt then the 8600GT just to ensure that it was not a lack of power from my 520W psu.

Mike, my gigabyte board had 4 of the ATX v12 pins covered so I initally ran it with the 4 pin yellow/black but then also tried the 8pin after removing the cover. My P5K-E was the same but I only ever needed to use the 4 pin, rather than the 8 also but it now also does not boot up, so Im leaning towards it being the CPU at fault.
I tried running with everything connect, then nothing but cpu and ram but nothing changed (this is on both motherboards).

The only thing I havent tried is using the jumper to reset the CMOS, is this instant after putting the jumper on or do I have to wait for 20mins or so?

While the Ultra X3 is a good PSU and WILL run the two cards, I have to agree that I would look to 1200W PSUs if I were going to do that. I hope you have a 30" LCD to take advantage of all that GPU power. Not that you'll see any difference anyway. Your CPU will bottleneck the system so bad I doubt you'll see a difference between one or two 4870X2s.

You didn't leave any MB standoffs in the wrong positions when you switched MBs did you?

It does sound as if you have CPU problems.

Ok, just tried it without the RAM but I am still getting the same result.

The 4870x2 require 2x6 to run but 1x8 and 1x6 is need to unlock the overdrive. Since the 1st time it didn't work I have been using the 8600GT, so that the GPU possibly being underpowered is not a factor.

@proximon:
No, there were no standoffs in the wrong position. Just out of curiosity it they had been would it case a short?
In terms of my setup I run with 3x22" but run some games in 5040x1050 with softth which renders everything through the main card but i run some of these without softth due to compatibility issues and hence I need an equally as powerful 2nd card to render (note that I know for both these to work crossfire has to be disabled).

As for the PSU I did alot of looking into it and have found quite a few people using the x3 1000w for 2x4870x2 running with 3.9ghz + cpu clock speeds stable and more HDD than myself, which was enough to sway me.

If you have another PSU to test with (motherboard and CPU only) it would point to CPU problem. If you don't yet have another PSU, get a Digital Voltmeter (DVM) and check all voltages are ok, if so, is CPU.

Mike.