I'm not sure, but i'll give you my opinion/guess.
1x coverage is older, and thus is much more widespread. If you live in an area which gets 'spotty' 3G coverage, switching the phone to 1x-only will probably save battery, cause then the phone no longer is searching for service half of the time. However, i can see where this other site is getting this from. Did they explain why 1x could drain more battery? My guess is that because its an older technology, they don't invest in making its reception methods anymore, so it is possible that picking up 3G is more 'efficient', simply because newer antenna technologies/scanning methods could be improved over the older methods. But like i said before, this is purely speculation.
thanks for the explanation, fisharefriends!
i did manage to turn off the 3g and have no idea whether it's because of that or not but - last night the phone was giving me low battery signal while i was making a phone call. this morning i turned off the 3g and now the battery level is back up to the halfway mark.
my phone tends to give the low battery warning a little early (it says it's low on battery then a little while later the battery level goes up slightly. so i have no idea if it's because of that or the fact that i turned off the 3g. but i will test it out and let you know if the battery life is any better in the next few weeks.