TweakTown published a review on the Linksys Velop Dual-Band AC3900
A quote from the article:
About a year ago we were in the beginnings of the Mesh Wi-Fi platform launch for many vendors. This included Linksys and Velop one of the top Mesh platforms of 2017. The Velop Dual-Band is the second iteration of the popular Mesh platform from Linksys, this time around a much smaller footprint for each node allowing them to blend into your home. In addition, Linksys has aimed to lower the cost of entry for many users creating an entry-level solution for those that didn't need the Tri-Band features of the original Velop platform.Linksys Velop Dual-Band AC3900 Review
Specifications for the Velop Dual-Band platform include each node being an AC1300 class device. This means across a three-node platform the entire system falls into the AC3900 class. That said we have 400Mbps on the 2.4GHz band and 867Mbps on the 5GHz band just as we did on the original Velop. The 2.4GHz band supports 256QAM while both bands support beamforming and seamless roaming technology.