RESOLUTION PROBLEMS WHEN NIGHT FLYING

Hi,

I am running the PMDG 737NGX under FSX with Acceleration. I have all the latest drivers. I am using a 42" HDTV for my main monitor and a 21" samsung for a second monitor. The screen resolution for the TV is set to 1920x1080 and I have the FSX set at 1820x1080. The problem I'm having is that everything is crystal clear and defined when flying in the daytime. The instrument panel is clear as is the outside view and my addon airports are all fine. However when I change to night, the resolution of the instrument panel becomes grainy like you can see the pixels, but the outside view is OK. When I switch views to the overhead, it is the same grainy panel as the MIP. I am using an Nvidia GTX 650 graphics card with an Intel i7 CPU. There's no stuttering or blurries and I get great frame rates

Anyone any ideas about this? I have used Nick Needhams tweaks for FSX but it doesn't make any difference.

Thanks

Rob