@Klaus/Keith - Updated 2 You are way off ... North and Southbridge tend to be each in the 2-3 Watt region. Analog->Digital, Digital->Analog - were is the problem?
-> notebooks - integrated -> no converting because of digital input for TFT (could be, that the panel has to use an external phy) - extern graphic chip (Geforce Go or ATI Mx) -> either also only digital or the panel has to have an digital->analog chip -> no problem
@Keith - 7h or more for P-M Its hard to believe that fact, because battery has to be really huge. I can think of 60-70Wh per Accu, which would give 7h only when the HOLE!!! notebook consumes 10W per hour an avarage. With lights on at the TFT, chipsets working, harddisk loading something, the CPU power consumption has to be in the MINUS region - mmmhhhh, is that possible? ;-) (I know the answer - Intel ...)