FeatherCoin giving a lot of rejected shares

[0150r]

I'm currently getting ~25% rejected shares with Feathercoin. When I mine for LTC with the same settings, I get ~1.5% rejected. What could be the problem? Are the blocks being solved too quickly for my machine to keep up? I am using stratum with LTC but not with FC (not sure if the pool supports it).

Config:

Code:

cgminer -o http://featherpool.com:9999 -u XXX.1 -p XXX --scrypt --temp-overheat 80 --temp-cutoff 85 --gpu-fan 85 --worksize 256 --intensity 16 --shaders 1792 --lookup-gap 2 --thread-concurrency 24768 --gpu-engine 1000 --gpu-memclock 1000

Output:

[2013-04-27 20:10:22] New block detected on network before longpoll
[2013-04-27 20:10:28] Accepted 07bdd288 Diff 33/31 GPU 0
[2013-04-27 20:10:28] Accepted 047b28b3 Diff 57/31 GPU 0
[2013-04-27 20:10:29] Accepted 076e5af1 Diff 34/31 GPU 0
[2013-04-27 20:10:37] Accepted 0174891f Diff 175/31 GPU 0
[2013-04-27 20:10:45] Accepted 049f7ae6 Diff 55/31 GPU 0
[2013-04-27 20:10:45] Accepted 027743f4 Diff 103/31 GPU 0
[2013-04-27 20:10:46] Accepted 04d4c028 Diff 52/31 GPU 0
[2013-04-27 20:10:48] Accepted 01e28a7e Diff 135/31 GPU 0
[2013-04-27 20:10:58] Accepted 0780ef3f Diff 34/31 GPU 0
[2013-04-27 20:10:58] Accepted 0742c047 Diff 35/31 GPU 0
[2013-04-27 20:10:59] Accepted 06961841 Diff 38/31 GPU 0
[2013-04-27 20:11:09] Accepted 0793c21d Diff 33/31 GPU 0
[2013-04-27 20:11:13] Accepted 062ef925 Diff 41/31 GPU 0
[2013-04-27 20:11:14] Accepted 03a70006 Diff 70/31 GPU 0
[2013-04-27 20:11:25] Accepted 02e43ef5 Diff 88/31 GPU 0
[2013-04-27 20:11:28] Accepted 026562b2 Diff 106/31 GPU 0
[2013-04-27 20:11:29] Accepted 07423b6c Diff 35/31 GPU 0
[2013-04-27 20:11:35] Accepted 0153b064 Diff 192/31 GPU 0
[2013-04-27 20:11:47] Rejected 03f11880 Diff 64/31 GPU 0  (prevhash-stale)
[2013-04-27 20:11:52] Rejected 01b7fc51 Diff 148/31 GPU 0  (prevhash-stale
[2013-04-27 20:11:52] Rejected 07b3c46f Diff 33/31 GPU 0  (prevhash-stale)
[2013-04-27 20:11:53] Rejected 03ac175f Diff 69/31 GPU 0  (prevhash-stale)
[2013-04-27 20:11:57] Rejected 00bd4e12 Diff 346/31 GPU 0  (prevhash-stale
[2013-04-27 20:12:01] Rejected 05afe58d Diff 45/31 GPU 0  (prevhash-stale)
[2013-04-27 20:12:23] Rejected 06aff83c Diff 38/31 GPU 0  (prevhash-stale)
[2013-04-27 20:12:33] Rejected 07f1381f Diff 32/31 GPU 0  (prevhash-stale)
[2013-04-27 20:12:34] Rejected 076d1162 Diff 34/31 GPU 0  (prevhash-stale)
[2013-04-27 20:12:37] Rejected 061833b9 Diff 42/31 GPU 0  (prevhash-stale)
[2013-04-27 20:12:39] Rejected 079d7e69 Diff 33/31 GPU 0  (prevhash-stale)
[2013-04-27 20:12:46] Rejected 02076843 Diff 126/31 GPU 0  (prevhash-stale)
[2013-04-27 20:12:54] Rejected 034f6994 Diff 77/31 GPU 0  (prevhash-wrong)
[2013-04-27 20:13:00] Rejected 03738e17 Diff 74/31 GPU 0  (prevhash-wrong)
[2013-04-27 20:13:02] Rejected 05bd2254 Diff 44/31 GPU 0  (prevhash-wrong)
[2013-04-27 20:13:04] Network diff set to 1.8M
[2013-04-27 20:13:04] New block detected on network before longpoll
[2013-04-27 20:13:05] Accepted 0030634e Diff 1.35K/31 GPU 0
[2013-04-27 20:13:06] Accepted 01c03586 Diff 146/31 GPU 0
[2013-04-27 20:13:06] Accepted 038c3f7e Diff 72/31 GPU 0
[2013-04-27 20:13:06] Accepted 031c796d Diff 82/31 GPU 0
[2013-04-27 20:13:14] Accepted 05ad2156 Diff 45/31 GPU 0
[2013-04-27 20:13:16] Accepted 01e946d3 Diff 133/31 GPU 0
[2013-04-27 20:13:17] Accepted 05b0529b Diff 45/31 GPU 0
[2013-04-27 20:13:18] Accepted 025e0d50 Diff 108/31 GPU 0
[2013-04-27 20:13:21] Accepted 006d4392 Diff 599/31 GPU 0
[2013-04-27 20:13:24] Accepted 0388c291 Diff 72/31 GPU 0
[2013-04-27 20:13:24] Accepted 052edb1b Diff 49/31 GPU 0

[JimmyFL]

I'm getting 8% (and slowly rising) using http://feathercoin.is-a-geek.com...
With LTC +-2%

[spiderJ]

Try lowering your intensity to 13. If I use GUIminer I can mine FTC at 20 intensity with ~5% stales, but with CGminer I have to use 13 intensity or I get much more stales/hardware errors.

[0150r]

Lowering to 13 drops my hash rate down to 315khash/s vs 600khash/s but didn't reduce rejection percentage. I don't feel that it's an issue with my hardware. The same settings work great for LTC with stratum. I tried mining on a stratum FTC pool and the rejected shares disappeared. That pool didn't get a decent enough hash rate to get enough blocks for a steady payout.

I wish I could get in on dontmine.me's pool because of their overwhelming hash rate (40% of the entire network right now). They should be getting a lot of the blocks. My current pool isn't getting many blocks which means small payouts for me

[0150r]

Using --no-submit-stale seems to reduce some of the rejections too.

[lanfeusst]

You should try --queue=0 --expiry=1 -s 1 maybe

It will ask every second for new work.

[willittobe]

After having the same issue on pretty much any non-stratum FTC pool (10->20% rejection/stales), and finding this thread, and doing some limited testing, I recommend:

--queue=0 --expiry=60 -s 30

Cuts down on stales for sure, so far about 10%, without effecting hash rate -16% as the previous 1-second update settings do.

I welcome further input or better settings!

[0150r]

Thanks for the help!

Do you have any recommendations for a good stratum pool? Featherpool.com is hurting without it. I'm losing 30-40FTC per day from the various calculators online for 1.750mhash/s with this pool.

[willittobe]

As far as I can tell there isn't one that is either a) working or b) open for registrations.

However, the admin for featherpool was saying he'd roll out stratum tonight/tomorrow sometime.

[willittobe]

Also, played with it a little more, --queue=0 --expiry=50 -s 25 might be slightly better for less stales, but starts impinging on hash rate slightly. YMMV

[0150r]

I am finding good results with a scan time of 5 and expiry at 5...I dropped from 1.788 Mhash/sec to 1.714 Mhash/sec with great results. 8182 accepted shares with only 269 rejected over the last 3 hours.