It's true. With 12.5 Claymore I have on my 280X 330-335 Sol/s with modded bios, overclocked memory and downvolted core.
Optiminer gives only 275-300 Sol/s.
Wow...can you please share your system/drivers/core/mem/timings/intensity/etc config? And which memory in cards?
1. System - Windows 10 Pro x64 CU, licensed with all latest updates.
2. Driver - AMD Crimson ReLive 17.4.1 - it's only one driver with wattman for GCN1 cards. But I have the same speed on all new drivers up to 17.7.2.
3. Card - ASUS R9280X-DC2T-3GD5. Hynix memory.
4. Stock freq. - 1070/1600. Speed not measured because I long time use modified bios with non standard memory timings.
5. Stock vcore - 1.2 V.
6. I use 1085/1665 freq. and 1.1 V core voltage.
7. Claymore's ZCash AMD GPU Miner v12.5. Intensity is 7. Monitor not connected to card. If monitor will be connected than Intensuty will be 6 to have enough vmem to video output to monitor. Speed difference between 6 and 7 intesity is about 5 Sol/s.
Command line:
ZecMiner64.exe -zpool(...) -zwal(...) -zpsw x -mport 0 -allpools 1 -i 7 -asm 1
I noted that Claymore ZCash miner is very sensitive to temperature of the card. If temperature is high miner became unstable. Even if temperature not critical. F.e. on my card on other miners (and Calymore other algo's miners too) my 280X stable mines up to 90-92 Celcius. But Claymore ZCash miner on temperature higher than 86 start to stop video driver...