you should have bought 2x1 gig sticks and 2x2 gig sticks so you still have dual channel. ddr2 does not do triple-channel, so that may be your performance slow down there.
HD isnt a signal(not saying your wrong krynn), HD is just a higher resolution picture. a digital signal(which we are talking about) sends more data over the airwaves then an analog signal, thus making the signal weaker. ive heard that the signal for digital will be stronger when analog goes...
Im still not understanding why they dont add all of this content to the original l4d. there is no reason to make a completely new game out of this. Heck team fortress 2 still gets a number of sales when they do the free weekends for the updates, why not do those for l4d?