Try testing with incrementally more and more sticks. See how many you can get to run at rated speed before adding another one starts slowing things down.

Could be what's happening (though it's unlikely) is your power sucks. Or it's your USB bus isn't able to support enough traffic. Or it could be yet another "Windows 10 blows goats and you should use something different" problem, because Windows 10 blows goats and you should use something different. Not just for 2Pacs, I mean, in general. For everything.