Problems with ASUS P5K3 Deluxe & EN8800GTX

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Hey Guys,

Recently picked up a new rig from your good selves last Sunday but I'm running into some difficulties.
Got it all put together but I'm really struggling on the system with 3D performance. The system is based on the ASUS P5K3 Deluxe Wifi Mobo with 2x1Gb DDR3 bundled, Q6600 Quad Core @ 2.4GHz and a Asus EN8800GTX 768Mb graphics card. with Vista Ultimate 32bit.

Installed the bundled Ghost Recon as a bit of an easy test after putting it together but it ran worse than on my old machine! Then ran 3DMark06 and came back with a score of ~3000 on default settings, not managing to get over 15FPS in the tests. Something is obviously wrong!? All the drivers/bios are up-to-date. I've even reinstalled Vista again from scratch carefully installing the latest chipset drivers before updating the rest of the system drivers. There are no error messages and on the face of it the system seems fine, until you load a game! The card is recognised as it should be in the PCIe x16 bus with correct memory/drivers etc. I've connected both the 6 pin power supplies to the card. I installed ASUS Smart Doctor which says the card is OK but it runs pretty hot @ 65+ °C idle despite good vent in the case. I've tried tweaking everything I can think of. Is there something stupid I've overlooked? Any help would be much appreciated as I'm tearing my hair out here! Is it possible it could be a faulty card?

On a semi related note, I tried the benchmarks from the Custom PC website to test the rest of the system. It failed to complete the image editing test (software issues I think rather than anything too serious), got a reasonable score of 1300 in the multi core video encoding (over reference 1000) but dropped way down in the multitasking to ~750 (from reference 1000) where it should have been close to it's previous score. Could this be part of the same problem or another issue entirely?

Total Specs:
- Intel Q6600 Quad Core @ 2.4GHz
- Asus P5K3 Deluixe Wifi with bundled 2x1Gb DDR3
- Asus EN8800GTX 768Mb
- 2 x 320Gb Samsung Spinpoint HDs in RAID 0
- Antec Quattro 850 W PSU
- Antec P182 Case
- Samsung SATA Optical Drive
- Samsung 22" TFT
- Vista Ultimate 32bit

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*UPDATE*

I have now tried/checked:
- graphics card 'properly' recognised with correct memory and in PCIe x16 bus
- connected with 2 x 6pin power
- all latest bios/drivers
- also rolled back through most old drivers but did not make a difference
- fresh Vista install and carefully installing the ICH9R chipset program before any other drivers
- flashed older bios versions to both graphics card (60.80.08.00.44) and motherboard (0501 & 0413) in various combinations but did not make a difference
- tried different bios settings on motherboard (turning off SpeedStep, C1E support etc.)
- tried most settings available on the NVidia Control panel
- loaded SMART DOCTOR which reports card is okay and confirms clocks are set as specified. Also indicates card runs at ~65°C idle
- removing SMART DOCTOR and other ASUS utilities as I read in a forum that this can have a negative effect

None of the above have made any difference, for better or worse. Reading through some other forums, these should have at least had some effect. Does this possibly indicate that there is a physical fault with either the motherboard or graphics card?

Thanks.

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If any of you guys at Yoyotech are actually reading this:

I just came up with the 'radical' (slight sarcasm) idea of putting the graphics card in the second physical x16 PCIe slot. The 3DMark score after installing the drivers jumped up to ~8000. Checking the bus speed it showed it was running at x4 as this is all the motherboard supports in the secondary slot.

When in the primary slot it shows up as x16 in CPU-Z and the NVidia control panel but obviously does not perform as such. I've checked the BIOS to check it's not forcing the slot down to x1 etc. Do you think this means there is a physical problem with the motherboard and it needs to be RMAd?

Thanks

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Just thought I would conclude this thread with the result in case anyone is searching with the same problem.

Brought the motherboard back to be tested. Chased it up after a week - they couldn't find anything wrong with the board but suggested the problem was due to dipping voltages on the (brand new) Antec power supply as they'd noticed this before with the same unit. I have to say I was slightly sceptical but one Coolermaster PSU later, everything's running as it should with a 3DMark score of 11500+!

Thanks guys!