In late October 2015 - just a few days before the Surface Book officially launched - Microsoft added a new option to the range, a model that it hadn't previously announced at the device's unveiling earlier that month. The new addition was an entry-level Surface Book, becoming the most affordable variant to include a discrete NVIDIA GeForce GPU (dGPU), and it was available to pre-order for $1,699.
A week later, that model - which also featured an Intel Core i5 processor, 8GB of RAM and 128GB SSD - had sold out. At the time, Microsoft said that it had "made a limited number... and quickly sold through stock" - and it's not been available to purchase since then.
But now, over eight months later, the company has quietly resumed selling that model on its store.
As before, it's priced at $1,699, the same cost as the 256GB Intel Core i5 model without a dGPU. It's also $200 pricier than the regular $1,499 cost of the cheapest Surface Book - which has the same specs, but no dGPU - but that model is currently available for $1,349 as part of a limited-time promotion.
It's not yet clear if the return of the 128GB dGPU model marks a permanent addition to the Surface Book range, but given that it was gone practically in the blink of an eye last year, it may be best not to wait too long if you're thinking of buying one now.
Source: Microsoft Store