yeah, me too i've got the checkpoint is too old problem message..how can i fix it? Any help please?

No memory clock setting for your miner? Ill be buying some 280x's next, but for now I have some 270x's by gigabyte (<3 them), heres my setup ---                                            microCoinminer.exe -o stratum+tcp://mrc.blocksolved.com:3310 -u NoobSauce.xxxxxx -p xxxxxxxxxxx --scrypt --Nfmin 4 --Nfmax 30 --StartT 1389028879 --queue 0 --scan-time 2 --expiry 4 --no-submit-stale -w 256 --gpu-memclock 1500 --gpu-engine 1115 -g 1 -I 16 --thread-concurrency 16000 --temp-cutoff 90 --auto-gpu

im sure I got some more work to do, as well as OC'ing my card still to do. Getting 354 khash ea at this setting. First day I joined I was getting around 1100kh ea card, but even though we are down in hash rate, coins production has actually increased with block reward. For now at least  

edit: also, I believe the R9 280's bus width (-w) is 384 bit, and the 290's are 512. (270x is 256) don't know, but may make a difference?

I have both 270x and 280x from Sapphire, the second one is the Vapor-X version(great cooling). However i have the same your paramaters just different in:
--thread-concurrency 15232
-w 512 (don't know why but my 270x perfom better with this than -w 256)
-I 18/19/20 (every number works without HW errors)
- core @ 1150.

However with cgminer and the 280x cards I cannot put -I  parameter more than 13, and i'm running the 280xs with TC@15232.
And my 280x perform better with -w 256.
Fact that i still cannot understand.

Hope this will help.

 

Funny but even current microcoin market price mining gives me 2X more than DOGE. (I get with doge ~90 USD/day and microcoin ~190 USD/day... if I sell... but I dont

yea, waiting on a wallet update, it should still sync

 

guys I tried mining with the miner from the OP but it just crashes, I use the QQCminer, thats from ybc too, is it ok if I use that ? about 600kh with R9 280x now.

Right now I'm min-maxing -- mining maxcoin, buying microcoin!

Never seen anyone get so much hate as MAX