GA-P35-DS3P limited PCI Express lanes?

RoundSparrow

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Dec 20, 2005
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Howdy,

The onboard Realtek network adapter with GA-P35-DS3P has been giving me some slight issues under Vista x64 at gigabit speeds. I've changed out switches and cables... and using the latest 2007-07-20 Realtek drivers... but about every 2 hours it drops packets for about 8 seconds. I've left pings going to other systems on the LAN to confirm it...

I have a GA-P35-DS3P that was working fine with a Nvidia 7900GS so I added a $19 Bytec 1x PCI Express Ethernet. My network problems went away, yey!

So today I added a second Nvidia 7900GS. I'm driving a third monitor, don't need SLI... and performance of the 4x electrical isn't a concern.

HOWEVER - the 1x PCI Express Ethernet adapter no longer works! I even have a spare, it it doesn't work. I switched between the two 1x PCI Express Slots.

My conclusion: 16x main graphics + 4x second graphics = no more PCI Express lanes for the 1x slots?

Anyone able to confirm that this chipset or motherboard has any such limitation?

Thank you.
 

RoundSparrow

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Dec 20, 2005
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I just tried a few more things

-- In the BIOS I disabled the onboard Network and Firewire - but did not help.
-- I installed the Intel chipset drivers (latest from Intel's site). Previously everything was fine with just stock Vista drivers...

Did not help.
 

rockyjohn

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The P35 architecture includes 1 PCIe x16 channel at 8 Gbs and 6 x1 channels @500MB each for a total of 3Gb or less than half the x16 slots. I beleive that board manufactureres have some flexibility in how they wire the 6 x1 channels - but you can see they would support less than half of an x16 slot. I don't know if one channel can be wired to more than one slot and if so how it prioritizes for multiple channels. Perhaps another reader can supply that information.
 

weilin

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i think the 22 lanes r split as 1x 16x lane. and then the 1x, 4x and other things divide up 4 more lanes. the last 1 or 2 are reserved for communication with the southbridge. If you wanna try to work with what you got, may i recommend you disable the onboard ethernet card (that usually consumes a lane)
 

cheapfrag

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Jul 18, 2007
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There was a review at NewEgg for this motherboard that said:
Cons: If you use the pci-e 4x slot, the other pci-e 1x slots won't work, and visa-versa. The northbridge heatsink could cause trouble with sone cpu fans. Stock intel works fine.

Other Thoughts: I was surprised at the motherboard not being able to use both the 4x and 1x pci-e slots at the same time.