A highend rig that does 3.4GHASH has the same diff as a 1.5GHASH rig. You should increase the difficulty to reduce the load on the server.
high end rig, you've made my day)))))))))High end rig is doing >8ghs ))
An average rig on yiimp is doing 1,5GHASH. So 3.4 is more than 2x the average rig. (3,4GHASH is based on 6x1070 @560MHASH each)
Are you using a private miner? Do you have any capture of your console?
What I have been able to get stable to my 1070 FTW are 490 sol / s with EWBF's