HD TV not showing in HD

[agentkuo]

That's the short explanation.

Here's the situation:

I recently bought a HD, 1080p, 40", Sony Bravia TV along with 2 HDMI cables.

My cable provider is AT&T U-Verse (just to clarify).

I connected the cable box to the TV with the HDMI cable.
I also connected my PS3 to the TV with the other HDMI cable.

The PS3 seems to be showing up in clear HD.
The cable, on the other hand, is not showing up in HD, it shows blurr, and clearly isn't in HD.

And yes, I am viewing HD channels, yes it's live (not re-runs originally recorded in SD or anything like that.)

The aspect ratio setting on the cable box is correct (set to 1080p).

The menus for U-Verse seem to be showing up relatively clear (Not sure if it's just because of the size of the TV or if it's showing in HD).

So does anyone have any idea what might be the problem?

I'm sure I could just call AT&T and deal with their bullshit to resolve the issue, but maybe someone here can help me so I don't have to.