Sounds like he just went from DVI to HDMI, which are both digital, one is just capable of Video and Sound. Now the change in the quality of wire may have improved that some but I'm no expert on that matter.
or since I changed my standard monitor cable/dvi adaptor to a gold plated dvi to hdmi cable, there has been a big improvement in picture quality on my desktop? There had definately been a change to my blu-ray movies, cant be sure about the desktop tho. I know the original cable is fine, connected it to the wife's rig. Maybe i'm going mad
"Gold" has no bearing on picture quality. It is merely you wanting that perception.
Gold is a better conductor of electricity, but with digital you're either going to get the 0's and 1's or you're not. I noticed an improvement with my current LCD monitor I bought 2 1/2 years ago. 20" ViewSonic didn't come with a DVI cable so I was using analog. I was getting some jittery lines in the upper corner of the monitor and instead of calling tech support for rma or whatever I bought a $8 cable off of Newegg. Picture quality improved along with the jittery lines disappearing.I still giggle at sales people pitching the $50-$100 HDMI cables, or the $35 gold plated USB cable at Best Buy.