Hi Claymore,
i get with R9 280x 15.5Mh only not 20Mh
How can i improve it ?
Its normal for 280x.
DEPENDING HOW HOT YOUR ROOM IS--
280X cards run hot and eat power. If your cards are overheating, you may need to downclock, and earn 15-16MH/s per card. If you set "-dcri 15" in your config, you will reduce the intensty of your secondary coin by 1/2 and give your 280X cards more room to breathe; they will run faster and at lower temperature. If you set "-cclock 1100", you will overclock your card, increase the hash rate, and increase the temperature of the card. A core clock of 1100 may not be stable for your card/rig, you have to check postings by other miners regarding overclocking. If you set "-tt 87", your card will self regulate, attempting to keep the temperature at or below 87 deg F. If you are in a hot room, your hash may be 15-16MH/s because of temperature throttling. My 280X cards made 22MH/s last winter, when the room was cooler, and the difficulty lower, and the DAG smaller.
All of this and more is in the README!!!.txt file, you should study it. --scryptr
scryptr - will the Stilt BIOS help maximize 280/280x for ETH mining? Thanks
THE LEGENDARY STILT BIOS MODS--
Stilt BIOS mods are from the days of LiteCoin (LTC) and its meteoric rise prior to the Mt. Gox hack There is a thread for those still interested.:
https://forum.ethereum.org/discussion/5937/gpu-optimized-stilt-bios-anyone-have-them] . Some users of the modded BIOS are able to point to the location of these legendary files, other users are downloading the entire archive to preserve the treasured data.
I have never flashed my recently ROI'd 280X cards. It can affect the resale value of your cards if detected. From what I read in the above Stilt BIOS thread, there is no guaranteed hashrate improvement, even if you flash your card. The thread is still short, and a good read. It points to the old, archived, 100+ page Stilt BIOS thread where I may find myself reading about the Black VooDoo of BIOS modding.
Bottom line, a BIOS mod is not a sure thing, and you need to save a copy of your original manufacturer's BIOS in order to set things back to default. --scryptr