It appears your computer's BIOS does not allow the ability to turn off your on-board video chip.
Your computer is stuck running dual monitors. In other words both on-board and add-on video card will always both be running at the same time, whether you have both hooked up to seperate moniotrs or not, both video processors will always be running.
I know this problem stinks, I have seen motherboards that insist on trying to run both video processors at the same time, thus restricting the system with the inferior on-board video processor.
You put in a nice 256 MB video card and the system drags along because the on-board video processor (lets assume it only has 100 MB of video memory) is still clocking with 100 MB of memory.
There is not a whole lot you can do in this case.
You may try disabling the on-board video through Windows, how-ever the BIOS will still try to run both video processors regardless of what you do inside windows, I've been there, done that myself years ago.
There is no safe way to disable the on-board video processor electronically either, that only causes damage to the motherboard and will certainly cause the motherboard to cease functioning properly, because this built in chip has to be functioning.
That is the down-side to having on-board video built into the motherboard.
Some motherboards allow you to disable the on-board chip and some do not.
Edited by MrBruce1959, 11 September 2010 - 09:49 AM.