Microsoft has released Windows 10 Insider Preview build 10122 to participants of the Windows Insider Program. This new build is now available for fast ring participants and you can download it right now from the Settings app (Update & Security > Windows Update). According to Microsoft's Gabriel Aul, this particular build is "buttery smooth" and a "nice improvement from 10074."
However, this build has one big bug for those of you with an AMD GPU. Apparently, Spartan and IE will crash frequently and the company is working with AMD to resolve the issue with an update that is slated to be released in roughly one week. Build 10122 will not be released to slow ring participants until the issue is fixed, so if you are on an AMD GPU, switch over to the slow ring for now (Update & Security > Windows Update > Advanced Options).