I think I can see why this happened. Kinda scary if true, in terms
of the cluelessness on Intel's part.
There is mention in the Intel user manual e35350001us of the
"Add2/MEC" option on the G35. Look at the block diagram on
PDF page 14. A DVI transmitter is tied to "something" on the
G35.
http://download.intel.com/support/motherboards/desktop/dg35ec/sb/e353...
Some background on SDVO for Add2/MEC here.
http://en.wikipedia.org/wiki/SDVO
This is the G35 datasheet. See PDF page 293, for how two SDVO outputs
share pins with the PCI Express. It could be, that the "DVI transmitter"
mentioned on page 14 of the user manual, is actually wired to the PCI
Express x16 slot. And that could be the source of interference. Plug
in the DVI, turns on the DVI transmitter, and the G35 responds thinking
it is driving an Add2/MEC card. That disables the PCI Express mode of
operation, and runs the slot so it can drive two SDVO devices. Effectively,
one SDVO device is hardwired to your motherboard.
http://www.intel.com/Assets/PDF/datasheet/317607.pdf
In effect, it is as if this thing is soldered in parallel to
your PCI Express slot. This is an Add2 card for DVI output. They
may have placed that chip and DVI connector, on your motherboard
instead. If it was a removable card, then by unplugging this,
you would have had unrestricted usage of your PCI Express slot.
It still would not have solved the problem, of not being able
to drive a DVI monitor at the same time as you use the PCI
Express slot.
http://www.provantage.com/fullsize/10265389.JPG
I would never have guessed such a thing, but that is as close as
I can get to explaining it for you. How did you even think of
trying VGA ? With so many DVI-only LCD monitors out there, there
aren't a lot of options to change to VGA when you want to.
Paul- Hide quoted text -
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