Some iPhone 7 models are slower than others, tests show

Apple says all of its iPhone 7 models are basically identical except for the amount of storage. The basic 32GB iPhone costs $649, but for $100 extra, Apple sells a 128GB version of the iPhone 7. For $200 extra, you can get a phone with 256GB of storage.

The screen, chips, and shape of the phones are identical.

But there's one big difference: The 256GB iPhone 7 has much faster write speeds than the 32GB iPhone 7, according to benchmarks being done on devices in the wild.

Other tests show the 128GB model is faster in terms of write speeds than the 32GB model, too.

That means that iPhones with more storage can, say, have big files transferred much faster than the entry-level iPhone 7. 

The most recent look at this issue comes from prolific gadget YouTuber Unbox Therapy. First, he uses a benchmarking app to show the difference in write speeds in raw numbers. Then he runs a real world test: transferring a 4GB copy of "Star Wars" from a Mac to the phone.

The 256GB iPhone 7 smoked the 32GB iPhone 7. The file transferred to the 256GB iPhone nearly a minute faster than the 32GB iPhone.

There's no consensus explanation for why this might be, but larger solid state drives often have faster write speeds than smaller drives. Also, Apple could be using a different vendor for its 32GB chips. 

It's not a dealbreaker. I don't transfer GBs to my iPhone often, and the bottleneck is usually the internet connection speed, not the limits of memory write speeds. But if I were buying an iPhone 7, this would certainly push me towards the models with more storage space.

Watch for yourself: