How to disable Intel HD on Inspiron 660

Kangyou Hong,

If the Bios Onboard Devices does not have the option, you will need to disable it in the Device Manager.

If I disable it in the device manager, I need to change video output to access Bios. It is an annoying way to access it.

Why the need to disable it?  If nothing is plugged into it it's not doing anything or using system resources.

You really cannot disable HD graphics that is built into the CPU.  However, a PCIe video card should be recognized and used once installed.  If not, you have a bios issue or motherboard problem.  Also, an HD 6750 is going to require a 6-pin power cable hook up and I am pretty sure a system with just a 300 watt power supply is not going to have one.  Therefore, you really cannot use this video card in your system anyway.  

once you insert a graphic card into the system it will disable the onboard graphics.. the backbone behind a good card is a powerful CPU. With that you can't go far wrong.

Once disabled is there any way to recover the 1 GB of memory that is consumed by the graphics controller?

The only Dells that have a user adjustable video memory size are the older machines that use AGP.  The memory on an on-board PCI-e bus video adapter is automatically adjusted by the BIOS depending on the amount of installed memory.  Most Dells capable of using a PCI-e video card automatically disable on-board graphics when a video card is present, so you wouldn't need to find a way to manually disable it.

If a device were disabled it would not be visible to Windows, however my machine has 8 GB of installed memory and only 7 available after installing a card.  Furthermore, if the device were truly disabled then using the PCIe card would allow you to see things like the post screen and the Dell logo during the boot process, or be able to view the BIOS or Boot menu.  This simply is not true, there must be a way to disable the onboard graphics cards, because newer Ivy Bridge Asus and Gigabyte UEFI motherboards give you that option.

If you believe Dell's spec sheet, the on-board graphics controller consumes a maximum of 256 MB of RAM, so it doesn't seem likely that the on-board is your problem.  It is my understanding as well that the graphics memory must be mapped into the same space as your RAM will occupy.  The computer spec says 8 GB is the maximum, so if the controller doesn't handle more than that, there is no room to re-map the memory displaced by your graphics card.

How did you disable the on-board graphics?  When I used to do this with older Dells, I simply used Device Manager to disable the on-board graphics driver and the BIOS switched video automatically to the installed video card.  I could even watch the boot-up, no need to attach a cable to the on-board port.

ivy bridge parts do not disable on board graphics any more when a PCIe card is used like old core 2 and sandy bridge did ... there is no way to manage gpu/cpu memory sharing either

Ah shoot I forgot about the 8 GB memory max, my GTX650 has 1 GB GDDR5 so that would explain why Windows doesn't allow for the full 8 DDR3.  I figured out the POST and Boot process, I simply had to disable the Secure part of the UEFI boot.  When I disabled the card I went to Device Manager and disabled it with a right click.