The answer here is no, if you are not using crossfire (2 video cards "scaling" as one) then the bandwidth between the PCI-E lanes is not shared. If you do crossfire, the PCI-E lanes are being shared to scale the two cards as one.
Well if the answer is no and the black PCIe16x lane #2 will not run at full speed if the 16x lane #1 is in use then Asus has A False Advertisement for the P5Q PRO Turbo they simply should have put a PCIe8x lane in for card two
Intel’s P45 block diagram shows the two PCIe lanes at 8x & 8x on the same MCH on the P45 chipset My Mother board Manual says Crossfire works at 8x & 8x otherwise the two PCIe slots are 16x each.
I googled the board and came across one person saying that the second PCIe16x lane only ran at 4x others say one lane stays at 16x but if you put a card in the second pcie16x lane then both switch to 8x and no one has an answer for me it’s the worse Conundrum I have ever had.
My theory is (Cross Fire is 8 by 8X) otherwise both PCIe lanes are and stay at 16X. Unless someone has the correct answer that I am looking for that’s what I think.
Well if the answer is no and the black PCIe16x lane #2 will not run at full speed if the 16x lane #1 is in use then Asus has A False Advertisement for the P5QL PRO they simply should have put a PCIe8x lane in for card two
There's no false advertising there.
There are notes in the specifications that state that the second X16 mechanical slot only works at an 8x link.
Michael, my question is why are you caring, you won't see any issue running @ 8x compared to 16x unless you were using a 5970 in crossfire or 2 x GTX 295,s otherwise, you should only see extremely minimal performance decrease.
Just bought an Asus U3S6 card which is 4x and both lanes went to 8x although the card is PCIE4x Version 2.0 and your right there is little to know diff in gaming performance
Next SATA v3 1TB Western Digital Black HDD Thanks for the input any one ells that has the same question its answered if you use both PCIe 16 lanes then they both will run at 8x so it is a FALS Advertisement LOL Still very good board at good price and the adapter card is running at full speed so I can’t complain.
Mobo P5Q PRO TURBO, CPU Q9650 not OC, RAM 8gigs ram,
GPU MSI R4850 2D1GOC Overclock to 700MHz GDDR Ram oc'd to 1000Mhz