Couple issues with SP4.
Doesn't work with R9 280(x)'s anymore. Crashes the driver as soon as they start up. They work fine with SP3.
Insane lag a few minutes into mining on any of my systems.
I have been using SP3 for about a month now because of these issues.
i have the same problem with GCN 1 & 2 i told SP about it,a few minutes into mining it starts submitting shares with a high ping due to lag, in my case even SP3 lags, what driver version are you using ?