About three weeks ago, some retailers started showing listings for a 13.5-inch Surface Book 2 with an Intel Core i5-8350U CPU. You might recall that when Microsoft initially announced the Surface Book 2, it boasted the new eighth-generation quad-core processors, but that was only for the Core i7 models; the Core i5 was still a seventh-generation, dual-core chip.
Now, it's official, and you can finally buy a Surface Book 2 with an eighth-gen Core i5. At this time, the new model, which includes 8GB RAM and 256GB of storage, doesn't replace the ones with a Core i5-7300U. They're actually sold side-by-side. When you go to configure your Surface Book 2, there's an option for a Core i5, a Core i5 (8th Gen), and a Core i7.
Interestingly, the eighth-gen Core i5 doesn't come at a premium, strictly speaking. Right now, the seventh-gen model is $200 off of its normal price of $1,499, but the eighth-gen model is also $1,499. Presumably, that sale on the seventh-gen model will continue until it sells out.
The base model, however, is not offered with an eighth-gen chip at all. This is the one with 8GB RAM and just 128GB of storage. Also, as you'd probably expect, there's no option for the 15-inch model to come with a Core i5. And as always, the Core i5 model still doesn't come with a dedicated GPU.
To check it out on the Microsoft Store, you can find the Surface Book 2 here.