If your neptune is running below 3.4TH you need to put better thermal grease on the boxes that are running slow. Check the dies and see which ones are not working. I use a amp tester to see which Neptunes are pulling low amps.
1) Start with your Neptune that is running slow. Unscrew the 6 torx screws on the case and remove the lid.
![](https://ip.bitcointalk.org/?u=https%3A%2F%2Fi.imgur.com%2FeWXdsHQ.jpg&t=664&c=0iMrWxGVQ-gb5g)
2) Unscrew the 3 torx screws holding down the heatsink.
![](https://ip.bitcointalk.org/?u=https%3A%2F%2Fi.imgur.com%2FH0WVqb3.jpg&t=664&c=Qhao6_cnX6c-Jw)
3) Remove the crap thermal grease with a paper towel.
![](https://ip.bitcointalk.org/?u=https%3A%2F%2Fi.imgur.com%2FmdIYdJQ.jpg&t=664&c=_kC7DTxJG1FgSg)
4) Apply some Diamond IC Thermal Grease
![](https://ip.bitcointalk.org/?u=https%3A%2F%2Fi.imgur.com%2F71fELnq.jpg&t=664&c=e0Q-LsZfqFK4wA)
![](https://ip.bitcointalk.org/?u=https%3A%2F%2Fi.imgur.com%2Fggf6CnN.jpg&t=664&c=MBUACtJhkJ79BA)
Put the heatsink back on and spread it around and then screw everything back together.
Out of 50 Neptune boxes I have had to do this on 12 of them. They are all working perfectly now.