Hi,

Try to Uninstall and reinstall GeForce GTX 660:

Driver files should always be uninstalled before updating to newer drivers or when removing an older NVIDIA card and replacing it with a newer card. To uninstall your current NVIDIA Display Drivers from your system, follow these steps:

1. Go into your Control Panel
2. Double-click the Add/Remove Programs icon
3. Select the NVIDIA Windows Display Drivers from the list of programs.
4. Click Change/Remove or Add/Remove button.
5. Confirm with Windows that you wish to continue with the uninstall

Note: A prompt appears asking whether you want to delete all of the saved nView profiles.
If you click Yes, all of the nView software and all of your saved profiles will be deleted.
If you click No, the nView software is removed, but the profile files are saved in the Windows\nView directory on your hard disk.  If you take advantage of the nView profiles, you may wish to keep your custom nView profiles.

Once the driver files have uninstalled, Windows will request that you restart your computer to complete the uninstallation.

Now, Install the drivers from the following link: http://bit.ly/13buori

Follow the below steps to launch nVidia Control Panel:

• Right-click on the desktop and select nVidia Control Panel.
• Click Start . Type nVidia Control Panel in the Instant Search box and press Enter.

Set a default graphics card for an application:

• Launch nVidia Control Panel.
• Expand 3D Settings and select Manage 3D settings.
• On the right-side window, click Program Settings tab.
• Under Select a program to customize: option, select the desired application.
• Under Select the preferred graphics processor for this program:, choose the desired graphics option.
• Choose a specific graphics card while launching an application:
• Right-click on the desired application icon and select Run with graphics processor.
• From the drop-down menu, select the desired graphics card option.
• Click Change default graphics processor... to change the default graphics processor previously selected for a particular application.

Change the screen resolution:

• Click Start .
• Click Control Panel.
• Under Appearance and Personalization, click Adjust screen resolution.
• Click the drop-down list next to Resolution. Move the slider to the resolution you desire and then click Apply.

Awaiting your response!

This is a copy paste from another thread I responded to, but I think it's relevant here. Using the onboard HDMI does not mean losing performance.

It will allow you full use of the Optimus switching between the Intel and nVidia GPUs. Therefore for normal daily use like web-browsing you can use the Intel for graphics which is quieter (and cooler), and the X51 will change to the nVidia when more horsepower is required e.g. gaming, and the noise isn't so much of a problem. This is how I have run my X51 for over a year and what it was designed to do.

Taomyn writes ... "Yes, I have all audio going through the on-board HDMI as well, full 7.1 surround."

I've got audio-via-HDMI working thru the nVidea because it appeared to be the only HDMI audio optio according to Windows.  Did you have to find and install a driver for the onboard HDMI, which is presumably managed by the Intel chipset(?)

Forgive this n00b question, but how does Optimus work with 2 physical HDMI ports?  Does it sense the nVidea HDMI is connected, but sends Intel graphics out the nVidea connector?

For clarification ... are you saying the performance difference between the HDMI ports is solely color saturation?  Also, is you audio going through HDMI as well?

Regarding Dell-Rajesh's driver installation ... I notice this driver is for 32bit Win7 & Win8(?)  Is this a mistake, or is it also for 64bit OSs?  Also, will these graphics drivers from GEFORCE also install the HD audio drivers for HDMI?

TIA  :)

Taomyn writes ... "Yes, I have all audio going through the on-board HDMI as well, full 7.1 surround."   I've got audio-via-HDMI working thru the nVidea because it appeared to be the only HDMI audio optio according to Windows.  Did you have to find and install a driver for the onboard HDMI, which is presumably managed by the Intel chipset(?)

I have the latest Intel HD 2000 drivers from Intel, and the latest beta from nVidia - I think both include something. Just make sure the onboard Realtek analogue driver isn't taking precedence (I think I disabled mine in the Sound Manager).

Regarding Dell-Rajesh's driver installation ... I notice this driver is for 32bit Win7 & Win8(?)  Is this a mistake, or is it also for 64bit OSs?  Also, will these graphics drivers from GEFORCE also install the HD audio drivers for HDMI?   TIA  :)

No you need 64bit drivers for a 64bit version of the OS

I never use Dell drivers now, currently on the latest beta 320.18 which works fine - only one thing that doesn't and it's very minor: the right-click menu on an application doesn't show me the "Run this on specific GPU" item, which is not a great loss (it's because nVidia classes Optimus as for laptops only, so the desktop driver omits just this part but everything else works just fine).

Forgive this n00b question, but how does Optimus work with 2 physical HDMI ports?  Does it sense the nVidea HDMI is connected, but sends Intel graphics out the nVidea connector?

Nope, only works if you use the onboard HDMI - think of your X51 as a very powerful laptop inside a small PC case with a desktop graphics, Optimus and better expansion.

No, there should be no huge difference in colour so it looks like either a configuration issue with the nVidia driver or a hardware issue with that HDMI port or maybe even the cable.

Yes, I have all audio going through the on-board HDMI as well, full 7.1 surround.