Try Claymore 11.3 with -h 460 and -dmem 1.
I tried it and I am getting the same performance
As i know new algorithm has lower hashrate on the same videocards, so it is weird that you have this result
Maybe because my card is 4Gb? Try to lower -h paramter step by 8. Try variants 452,444,436, etc. If speed will be lower, try to increase.