Having trouble getting a system to post with PCIE card in it

[hoorah]

My uncle recently gave me a TV tuner card out of his dell computer. He recently got u-verse and has no use for it. I believe its a dell-branded card, but its basically a ATI Theater 650 Pro, PCIE (small 1x connector).

I'm trying to install it in a Gigabyte K8N-SLI motherboard (Socket 939, my HTPC2 in my sig). Its got 2 PCIE 8x slots and 2 PCIE 1x slots.

The system starts up and runs fine on its own with the 6600GT in the top PCIE 8x slot. If I add the PCIE TV tuner to the 1X slot above it, the computer won't post. Due to a frankenstein cooling system project with the video card, the 2nd PCIE 1x slot is blocked unless I move the 6600GT to the second PCIE 8x slot, but the system won't post with the card in this slot.

My first guess was power supply issues, but I tested with a known good 250W supply and got the same results. Using my watt-meter, the system uses about 100W at boot and 80W at idle, so I'm suspecting I have plenty of power to add one card(but not ruling it out). Some tests on the theater 650 card from awhile ago show the card uses about 30W. I realize 250W is low, and I do plan on testing with a bigger power supply as soon as I can, but I'm suspecting its something else.

Is there anything obvious thats jumping out at anyone about the PCIE 8x / 1x configuration that I'm missing? For example, are there different versions of PCIE 1x (1.0, 2.0, etc) that might cause the card not allow the system to post? Any PCIE power requirements / power-split boundaries I'm not aware of?

I also find it odd that if I move the graphics card to the second PCIE 8x slot, the system won't post either (even without the TV tuner installed).

The power supply I'm using does not have the additional 4 pin power connector that my newer ones have, could that be why? Sorry about my ignorance on that subject.

Short Version:

Motherboard has 4 sockets - 2 PCIE 8x, 2 PCIE 1x.
Have one GPU - 6600GT, 1 TV tuner (theater 650 pro)
GPU in 1st PCIE 8x slot - system posts
GPU in 1st PCIE 8x slot and TV tuner in 1st PCIE 1x slot - No post
GPU in 2nd PCIE 8x slot - no post
GPU in 1st PCIE 8x slot and TV tuner in 2nd PCIE 1x slot - N/A due to GPU cooler interference.

Card works in other systems.

 

[tcsenter]

Do you have the Gigabyte SLI switch module installed in either normal or SLI mode? If you don't have this module installed, then the only PCI-E slot that will work is the blue x16 slot (but it only works @ 8x). Check section 1-6 of the user manual for usage of this module and valid configurations.

There is also a beta BIOS available (F10E) that "improves VGA card compatibility". Don't know what that means but it might be worth a try.

Otherwise, it sounds like a BIOS bug/glitch. Not terribly rare or uncommon on older first-generation PCI express boards.

 

[hoorah]

Yeah, the SLI chip is in the "normal" mode, the same way its been set since I bought the board (so much for going SLI....)

I updated the BIOS at one point, but I'm fairly certain it wasn't a beta. I went on the gigabyte website and didn't see any beta versions, but I probably wasn't paying attention. I'll give it a look-see again.

I've been doing some reading and I'm actually leaning more back to the power supply issue. I've been reading about the various ATX power specs through the years, and how the newer boards rely more on the 12V line than the 3.3 and 5V lines like the old boards.

The power supplies I've tested with (150W and 250W) are both older ATX units with 20pin connectors and no P4 4 pin CPU connectors. I've run plenty of boards (including this one) with just a 20-pin connector, but they all were 350+ W units and much newer. I am now suspecting at this point that even though I have plenty of power capability on the 3.3 and 5V lines, I don't have enough on the 12V line, even though I can power the CPU and 6600GT just fine on the 150W power supply.

I've heard that the extra 4 pins on the 24pin power supply go towards supplying additional power to the PCIE connectors, but I don't know if thats true or not, haven't been able to verify. If thats true, that would certainly fit the scenario.

 

[mfenn]

Have you tried the tuner in the second x8 slot?

 

[VirtualLarry]

The power supplies I've tested with (150W and 250W) are both older ATX units with 20pin connectors and no P4 4 pin CPU connectors. I've run plenty of boards (including this one) with just a 20-pin connector, but they all were 350+ W units and much newer. I am now suspecting at this point that even though I have plenty of power capability on the 3.3 and 5V lines, I don't have enough on the 12V line, even though I can power the CPU and 6600GT just fine on the 150W power supply.

I've heard that the extra 4 pins on the 24pin power supply go towards supplying additional power to the PCIE connectors, but I don't know if thats true or not, haven't been able to verify. If thats true, that would certainly fit the scenario.

I'm amazed that that board powers up and runs without a P4 4-pin ATX12V power connector. I thought that those were basically required, on boards of that era and newer.

 

[hoorah]

Have you tried the tuner in the second x8 slot?

Yep. No go there either. Pretty sure its the power supply limitations.

 

[hoorah]

I'm amazed that that board powers up and runs without a P4 4-pin ATX12V power connector. I thought that those were basically required, on boards of that era and newer.

Yeah, it is a bit odd, but it does work. The chip in it is a 3200+, so its relatively low powered for that board. I want to say I've even run my 4200+ system temporarily without the P4 connector but I can't be certain.

I'm pretty sure now that the extra 4 ports on the 24 pin connector are for the PCI express slots, which would explain a lot. Being that its an older power supply (and a low power one to begin with), it doesn't have a ton of power on the 12V line, and between the newer CPU and the PCI express port having to share it, it just doesn't have enough even though the total wattage should be okay.

I was going to get a 20-24 pin adapter to see if that helped, but I think I'll probably just wait for a special sale from newegg on a decent (and more recent) 300W unit and that should be more than enough. The system works now without the TV card so I'll just be patient I guess.

Thanks for the help!