HD4870 HDMI-HDMI Full HD problem

[Akos]

Dear all,

this is my first post so I hope this is the right place to ask.

My problem is the following: I've recently bought a Full HD TV a Samsung LE32A656 and I hooked it up to my Radeon 4870 with HDMI-HDMI cable with the provided DVI-HDMI converter. It all goes OK until 1366 resolution but when I go beyond this, ie. to 1920X1080 the picture goes into underscan, the colours fade out and the sharpness decreases to unimaginable levels. I've tried with 4 cables, from the 10 dollar ones up to the 100 dollar types and all the same. If I plug it into analogue mode over D-sub it's all fine except that the image is not that sharp and I get some ghosting on the characters (ie. I have a lighter tone vertical line after every word and black edge) but I guess it is normal for non digital signal.

Then I thought it may be a VGA issue and put in my back up card, an X1550. After installing it and rebooting it came the big surpprise: it's all very nice and sharp over the HDMI without any overscan problem (so the pixels are mapped OK straight from the start!

Also I've asked my friend to bring over his Radeon 4870X2, he runs 40" full HD samsung and it is OK there for him (though he also has the overscan issue, so you have to manually adjust the size from control center). In my machine we got the same problem exactly as with my 4870. I run XP SP3. COuld this be a Radeon HD4800 series specific problem? ANybody else noticing the same? ANy advise what am I doing wrong?

Thanks in advance,

Akos

[martini161]

how long is the run?

[Apoptosis]

A friend of mine has the same 6 series Samsung TV you have and doesn't have any issues with it. Have you tried setting it at 1920x1080 and then rebooting the system with the TV powered up first?

Just curious what color is the DVI to HDMI adapter... Black or Grey? (Many of the very first HDMI adapters that were black and said revision A and B were faulty as I have 10+ dead ones here)

[Akos]

HI guys,

many thanks for the comments. The cables were all 2 meters (7 feet) long, so it should not be an issue, and also the 100 dollar one was full gold connections and oxyigen-less copper wires.

Apoptosis, what VGA does your friend run it with? As i've said on the X1550, which is also a Radeon card, it's all OK with the very same OS and driver. It seems to be a HD4800 series issue as it produced the same on two cards (though one was a 4870X2). I use the adapter by Ati which is grey and it worked fine again with the X1550. So it definitely must be a VGA and/or driver issue. VGA I'd rule out because on D-sub it is very good, only not that crisp. I'll try to post pics later.

Also will try what you suggest, booting after TV is powered up.

Any more ideas are welcome!