Prior to this weekend, Microsoft only put the latest 8th generation Intel Core processor only in the high-end configuration of the Surface Book 2 notebook. To get the 8th gen part, you had to opt for the Core i7 version of the notebook; the base Core i5 version used an older 7th generation processor. Rumors that the Surface Book 2 would get an 8th generation Core i5 Kaby Lake-R upgrade first surfaced earlier this month.
Microsoft has confirmed that rumor and given Core i5 shoppers access to a Surface Book 2 configuration that packs the 8th generation quad-core Core i5-8350U processor under the hood. The caveat here is that to get the 8th gen Core i5; you do have to go with 256GB of storage. The configuration with the 8th gen i5 chip under the hood pairs the CPU with 8GB of RAM and 256GB of storage for $1,499 from the Microsoft Store. That is $300 more expensive than the base Surface Book 2 with the older processor.
The base unit, which is still available, has the dual-core 7th gen Core i5, 128GB of storage, and 8GB of RAM for $1,149. If you opt for the 7th gen Core i5 machine with 256GB of storage and 8GB of RAM, it costs $1,299 with the current $200 discount; the base 128GB machine has no discount. It's unclear at this time if Microsoft intends to continue offering the original dual-core 7th gen Core i5 configuration on an ongoing basis, or if the machine will be retired when the supply runs out. Both the new and old Core i5 configurations appear to be available and in stock as of writing.