I would like to relate my experience using PrimeGPU. I purchased a license for 1 card on Apr. 10 for the price of 35 XPM. I ran the miner with the recommended settings of 1150/1500 and Catalyst 13.9 on my Gigabyte OC R9 280X until Apr. 17. During that time I found 3 10-chains and 0 blocks. Difficulty was about 10.6 when I began. The "time" value was around 200-210 and CPD around 1.35. I've since switched to Claymore's miner and have found 3 blocks in 2 days, which on the pool and with developer fee translates into about 8 XPM so far. Maybe I was just very unlucky with PrimeGPU and lucky with Claymore or maybe 1 card rigs just aren't enough for solo, I don't know for sure. But I do know seeing the license price drop a week after I bought one only adds insult to injury for me. I am definitely regretting buying this. If anyone has any suggestions to improve performance, I'd appreciate them.