The only explanation I can think of is that Dolphin's output is a filtered texture, and filtering does have a bigger performance impact if you're filtering the same image on a screen with four times the pixels. Running it in low-res mode gives you a 1440x900 image with no filtering (aside from what Dolphin does itself), so that's much less work.
<@skid_au> fishing resort is still broken: http://i.imgur.com/dvPiQKg.png
<@neobrain> dafuq
<+JMC47> no dude, you're just holding the postcard upside down
----------------------------------------
<@Lioncash> pauldachz in charge of shitposting :^)
<@neobrain> dafuq
<+JMC47> no dude, you're just holding the postcard upside down
----------------------------------------
<@Lioncash> pauldachz in charge of shitposting :^)