The rumored 12″ MacBook retina with newfangled trackpad and “fan less” design is a rumor as exciting as the iPad mini. But there’s one thing I’m questioning about the reports: the 2304 x 1440 resolution. That would be 1152 x 720 logical pixels, and Apple’s smallest display in recent history. Even the original PowerBook G4 was 1152 x 768. Only 1024 x 768 displays have less room on them. The current panel used for the 15 and 13 retina models is the same dpi, and extrapolating the same dpi (they’re all in the 220-ish range), this proposed resolution would be too.

The non-retina 11″ Air currently actually has the highest non-retina dpi of any of Apple’s products, and doubling that from 132 to 264 still would be far below iPhone / iPad mini territory (although I would love a laptop at that dpi too). This wouldn’t account for the increase in size from 11 to 12 inches, which is especially interesting considering just how much bezel the 11″ has today. Dialing up from there just a tad to a dpi of 283 could give the same 2880 x 1800 resolution as the 15″, which would be definitely eek this product into “pro” territory, and most importantly offer “looks like 4K” as a scaling mode, which would be nice since my 20/10 eyes have no trouble with 1080p points at 12″. 3840 mode on the 15″ is just around 300dpi, so 283 would still be lower than that virtual resolution.

So, predictions from most to least likely for resolution:

• 2x1280x800 = 2560×1600
• 2x1440x900 = 2880×1800

I think the extra “inch” will be used to make the laptop taller and 16:10 instead of 16:9. I don’t expect any resolution we haven’t seen before because the math works out so well with the scaled modes we currently have.

My original 11″ Air and original 15″ retina are both fine machines in perfect working order, but I will continue to dream of a machine that combines the best of both worlds (the retina 13″ is what I’d call a ‘compromise’). I hope I’m not too disappointed this fall.