HTPC and overscan

Hey guys, looking to buy my HTPC in the next 24 hours but it depends on the following.

I have my desktop hooked up to my Onkyo AVR which is hooked up to my TV via HDMI
ubuntu 12.04, nvidia GTX460

I've used the popcorn hour xbox ps3 and many other devices and do not get overscan. IF I get an HTPC will it be overscan?

I can't fix this withing my tv options or AVR options. I've looked for 3 days, I think I can fix within XBMC config for resolution.

But will overscan occur on new setup?

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EDIT

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I went and bought a dumb boxee box because i know it works with my tv. HTPC may not and I dont want buy one if it wont look right