Please help to decide whether HTPC upgrade is needed with probable RGB full/limited issue

My current HTPC has a ATI 4870 connected to Panasonic plasma 50PZ80 via DVI-HDMI cable. The OS is Win7. The GPU has only DVI outputs and TV does not have PC/game option. Sound is routed to Marantz 6003 via SPDIF.

Problem: Netflix is now my go-to source for video but scenes in the dark/night are too dark to see what is going on.

I have read through the forums and vaguely understand this might be a RGB full/limited problem. My 4870 sends RGB full to my TV which is RGB limited. This explains, I think, why if I adjust the TV brightness I got more details in everything EXCEPT black areas. The blacks just turn to blotches of uniform grey instead of showing more details. Unfortunately, my 4870 only has DVI outputs so the option of selecting RGB limited in ATI CCC is not available. For other video sources (DVD, ripped video), I do get more details on the black by dialing up the brightness level but I almost never need to. What I don't understand is why this only happens with Netflix? Shouldn't any video passing through the GPU suffer the same problem?

I am not looking for a perfectly calibrated TV and mostly I just take the setting recommendation from the forum to set my TVs. I just want a decent picture and right now Netflix is not watchable for a lot of its contents, yet it has become my main source of video entertainment. Is this a RGB full/limited issue or is this a Netflix issue? I don't mind upgrading my HTPC if the 4870 really is the culprit but I don't want to spend the money and time to replace a HTPC that took a lot of time to set up just right.

Thanks,

DM

My card did not come with ATI dongle and I was told that audio pass-through is not possible with this model. I used the registry hack using LevelsWizard found on this forum and maybe just my eyes playing tricks but it seems I was able to pick up a bit more details in black. Is there a difference between ATI dongle and registry hack solution? Netflix still appears to be too dark though, which may not be RGB limited issue. Also curiously is that none of the ATI CCC settings seems to have effect on Netflix. This is really annoying considering that I have been able to adjust KMplayer, MPC and VLC to my likings and many Flash based streaming services allow me to adjust brightness level as well.

So am I correct in concluding that the darkness level from Netflix cannot be solved by replacing the 4870 with a more modern card?

Thanks I ordered an ATI adopter and will test again once it arrived. Just to add that the registry hack used by LevelsWizard does work in activating RGB limited. I did some testing and was definitely able to see a difference i.e. I can see more shades of black in black hairs whereas it was mostly a block of same black. I am glad to get more details but this does not not completely solve the darkness issue with Netflix. I am wondering if this is due to Netflix/Silverlight does not use HW acceleration so the GPU does not alter the video window because the CPU is doing the decoding. I think on my other HTPC, which is Nvidia based, video processed by CPU tend to be darker than GPU processed ones. My understanding is that VC1 used by Netflix is not HW enabled in Silverlight.