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P8Z68-V/GEN3 Challenge!

  • Asus
  • Graphics Cards
  • Corsair
  • Motherboards
Last response: in Motherboards
February 4, 2012 8:42:32 PM

OK, this is the challenge should you choose to accept it.

I recently received the following PC - custom built:

CPU: Intel Core i7 2600K
CPU Cooler: Corsair H80 Water Cooler
Operating System: Microsoft® Windows 7 Home Premium 64-bit
Motherboard: Asus P8Z68-V/GEN3
Memory: 8GB Corsair 1600mhz Vengeance (2x 4GB)
Hard Drive: Corsair 120GB Force3 SSD S-ATAIII 6.0Gb/s
Optical Drive: 10x Blu-Ray RW S-ATA
Graphics card: PowerColor PCS+ AMD Radeon HD 7950 3GB
Case: Corsair Carbide 500R White
PSU: 850W Corsair TX

I am having some serious problems though in getting the graphics card to work. It worked fine for around a day. Next morning the screen was blank and nothing could be done.

To cut a long story short I have extensively tested both this current graphics card (the HD 7950) and an older one (an HD 6870) and found the following:

- The HD 6870 always works no matter what in this new system, no issues whatsoever;
- The HD 7950 works in an older computer that i own, no issues;
- The HD 7950 will only work once within the new system, and then on subsequent reboots the VGA LED on the motherboard will stay on red (indicating that there is a graphics card issue).
- If I remove the 7950, put in the 6870, and boot, everything runs fine. Then (sometimes) if I re-insert the 7950 it will boot up fine the first time, but on subsequent reboots, I get the same issue, (i.e the constant red LED and no image).

I am totally mystified.

I have reset the BIOS to standard optimized settings throughout these tests. So I don't believe it is anything to do with overclocking. I plugged in both power cables to the graphics card each time, so it shouldn't be a power issue.

I have tried the 7950 in different PCI-E slots, to no avail.

Any ideas would be gratefully received.



More about : p8z68 gen3 challenge

a c 207 Ĉ ASUS
a b U Graphics card
a c 717 V Motherboard
February 4, 2012 9:57:22 PM

The PSU might be bad, it would explain your situation. Try different PCIe power leads, but I doubt it will remidy the issue; alternative is to piggyback off the other PSU (there's a couple ways to do that). Otherwise the drivers might be corrupted; uninstall and manually remove the AMD files.

IMO it seems more like a power issue.
February 4, 2012 10:05:33 PM

Thanks for the reply.

Couple of further questions arise:

With respect to drivers possibly being corrupted, this cannot be if the computer does not even get to the BIOS screen, can it?

In terms of piggybacking of my old PCs PSU, do you mean leave the card in the new PC, but connect the old PSU to it? (I assume the old PSU would need to be on before I switch on the new PC)....?

I will try alternative PCIe power leads first though... less hassle.


Related resources
a c 207 Ĉ ASUS
a b U Graphics card
a c 717 V Motherboard
February 4, 2012 10:23:36 PM

I am trying to do this on my iPhone.

If it fails before the drivers are loaded then it's not the drivers and would seem to be the PSU.

If you use the other PSU to borrow PCIe power then google PSU paper clip test and from the donor PSU / PC you can either remove the PSU or pull the 24 and CPU power (side to side) or remove the PSU; your choice.

Clearly if that solves the problem the you'll know it's the PSU. Components fail and Corsair is a good company.
February 8, 2012 8:46:31 PM

Sorry all, but you are not responding very well to this challenge.

As I said have tested the HD 7950 in my 5 year old PC system and it works perfectly. In my new system, the only graphics card I can get to work is the HD 6870 I bought last year. My new system cannot work with either the new HD 7950 or the HD 6970.

I have tried both sets of PCIE power cables. The effect is the same, the LED for the graphics stays lit.

I have searched extensively on the internet and I have not found anything similar to this problem (I am happy to be proved wrong :non:  ).

I feel it is something to do with the motherboard, I do not see how it can be the power if the HD 6870 works (which I believe draws more power than the HD7950)

a c 207 Ĉ ASUS
a b U Graphics card
a c 717 V Motherboard
February 8, 2012 9:35:12 PM

Yes, I 'get' it. The only explanation that comes to my mind is the PSU.

If you feel it's the MOBO and not a PSU or perhaps a 'seating' problem then breadboard minimal configuration and remove the MOBO from the case.

Failure, well the MOBO is outside its case and ready to be packed and shipped-off via RMA.
February 15, 2012 9:39:15 AM

Update: Tried the old breadboard trick, and the HD7950 worked. I went into windows, even reran the windows experience index, everything was fine. Then when I restarted the computer I get the same issue, the vga led stays lit. I put the old card back in, works fine. Put the new card back in, same issue, led stays lit.

This was a very similar experience to when I first got the card, it works, then on reboot does not. It is almost as if something "resets" after a period of time, that allows the card to work again (for just the initial boot).

jaquith, so does this sound like a PSU issue still? I know very little about PSU issues (except that they can be notoriously difficult to check/confirm). Why do you think it is a PSU issue?

Thanks for any light you can shed!

a c 207 Ĉ ASUS
a b U Graphics card
a c 717 V Motherboard
February 15, 2012 12:13:06 PM

If the cycle is indeed the exact same, to rule-out Windows run MSCONFIG select Diagnostic and test. Question, did you try to flash the GPU or do you have any GPU OC/acceleration Apps installed? If so then uninstall; Diagnostic 'should' disable rouge Apps.

The primary symptom of a failing PSU is erratic behaviors especially upon startup and load to the PSU...
February 19, 2012 9:01:10 AM

Thanks for the reply.

No I have not tried to flash the GPU. I did have MSI Afterburner installed and AI Suite, I uninstalled them both and started the computer in dignostic mode but no joy.

I did inadvertently discover that if there are no power leads connected to the card (or just 1) then the computer POSTS normally, but (maybe somewhat obviously) I cannot see an image, probably because of the lack of power to the card.

This maybe suggests a PSU issue, as you have stated (a few times!).

I really am reluctant to send this computer back though since the service from the company I bought it from is absolutely terrible and I fear they will just send the PC back to me in its current condition (or just lose it). Maybe the only option though...

Do you know if the HD7950 draws more or less power than the HD6870?? I thought these cards were getting more power efficient!!


a c 207 Ĉ ASUS
a b U Graphics card
a c 717 V Motherboard
February 19, 2012 10:51:41 AM

I failed to ask if you OC the CPU, if you also have a 'bad' CPU OC then that too would explain the problem.

Upon 'startup' or 'waking' (C/S/P states) the power spikes of either a CPU or GPU often cause issues, heck sharing a common SATA power lead with the primary OS drive can cause bootup issues; power is a funky thing.

Therefore, the difference between load of either HD 7950 and HD 6870 doesn't interest me as much as the power upon startup.
February 20, 2012 7:03:49 AM

I was OC the CPU (nothing drastic though), but I promptly set everything back to stock as soon as this issue appeared in order to remove this from the equation.

I understand what you are saying about the overall power requirements being of the most importance, but my point was that the only difference between a working system and one that isn't is the graphics cards and so they are the only variable in terms of power.

Anyways, I decided to try out your suggestion and remove the power to two of my SATA hard drives, this leaves just the SSD. And the system powered up fine!! Trouble is I am now not sure whether this is one of those random occurrences or it is genuinely to do with the SATA drives.

I thought I would ask (whilst the computer actually works with the new card) if there is anything I can do to conduct some checks/tests?? This could be the only chance since when I restart I may be back to square one.

February 20, 2012 7:52:05 AM

Too late! The screen just when all strips of color, so the card had clearly crashed. I restarted the machine (withouth the HD's connected) and got the same vga red led, and no POST.

Sooo, could be if I used this new card long enough in the old machine it would have crashed there too. Anyway, I am RMAing this graphics card and getting a refund, life is just too short.

The company that made the PC will (hopefully) send me another graphics card separately (after a month of waiting), and if this does not work I will send the whole PC back.

Thanks for all your help.

a c 207 Ĉ ASUS
a b U Graphics card
a c 717 V Motherboard
February 20, 2012 12:26:36 PM

Seem pretty darn clear power is playing a major role in this problem.

Next IF the BIOS environment changed from when you installed the OS to now i.e. requiring different drivers then that too can cause sudden shutdowns.

Example BIOS changing from IDE <-> AHCI <-> RAID. Intel RST has a newer version -> and run FixIt ->

Further, I do not recommend using ANY of ASUS's Utilities that are used to OC the CPU or GPU e.g. ASUS AI Suite II; this is not limited to ASUS, I don't recommend any OEM OC utilities.

Next, make sure the following is set if using d-Mode:
BIOS for d-Mode
Initiate Graphic Adapter -> PCIE/PCI ; otherwise BSOD
iGPU Memory 64MB ; or more
iGPU Multi-Monitor -> Enabled ; required

ref -

See if any of that helps.