Halo 3 was recently added to Xbox 360's Games on Demand service, but Microsoft has not confirmed that the longer-than-normal load times present on a hard drive installation were fixed for the digital release. Developer Bungie had previously been quite clear that Halo 3's design functioned best when not installed on the Xbox 360's HDD. Bungie Community Director Brian Jarrard told Kotaku yesterday that to the developer's knowledge there was no additional work "done on the code to optimize the game for HDD installation."
We've patiently been awaiting a response from Microsoft on this issue and will update as soon as we receive one. In the meantime, we'd steer those Halo 3 latecomers toward a brick-and-mortar retailer.
Update: Microsoft's official response can be found after the break.