High Error Rate vs. Poor Performance on new 7850, scrypt mining

[EWold]

I just received this Powercolor 7850 from the egg, http://www.newegg.com/Product/Product.aspx?Item=N82E16814131562, and I have been having problems getting it run run faster than my 6850.

I've set the intensity to 12 and I still get HW errors.  I also get artifacts.  

I've set my batch file with;

cgminer --scrypt -o [removed pool and workers] --shaders 1024 -I 12


 cgminer version 3.7.2 - Started: [2014-04-04 11:57:51]
-------------------------------------------------------------------------------
 (5s):222.4K (avg):225.6Kh/s | A:3088  R:0  HW:49  WU:149.3/m
 ST: 2  SS: 0  NB: 9  LW: 112  GF: 0  RF: 0
 Connected to removed
 Block: 5f40cb59...  Diff:5.75K  Started: [12:12:25]  Best share: 1.56K
-------------------------------------------------------------------------------
 [P]ool management [G]PU management [ S ]ettings [D]isplay options [Q]uit
 GPU 0:  54.1C 1917RPM | 222.3K/225.6Kh/s | A:3088 R:0 HW: 49 WU:149.3/m I:12
-------------------------------------------------------------------------------

 [2014-04-04 12:16:28] Accepted 051200c6 Diff 50/32 GPU 0
 [2014-04-04 12:16:56] Accepted 033ec577 Diff 79/32 GPU 0
 [2014-04-04 12:17:34] Accepted 04658004 Diff 58/32 GPU 0
 [2014-04-04 12:18:07] Accepted 066139d2 Diff 40/32 GPU 0
 [2014-04-04 12:19:18] Accepted 03afd41f Diff 69/32 GPU 0
 [2014-04-04 12:19:26] Accepted 05476ad1 Diff 48/32 GPU 0
 [2014-04-04 12:19:40] Accepted 03ee95a3 Diff 65/32 GPU 0
 [2014-04-04 12:20:00] Accepted 0207754b Diff 126/32 GPU 0
 [2014-04-04 12:20:00] Accepted 01422215 Diff 203/32 GPU 0
 [2014-04-04 12:20:05] Accepted 0599d0a2 Diff 46/32 GPU 0
 [2014-04-04 12:20:06] Accepted 060e993b Diff 42/32 GPU 0
 [2014-04-04 12:20:11] Accepted 03826d24 Diff 73/32 GPU 0
 [2014-04-04 12:20:16] Accepted 07ad8711 Diff 33/32 GPU 0

The thing that isn't funny, I've been running my 6850 1GB from Gigabyte for months at I 16 without specifying any other type of variables and it runs at 225KHs with rarely an error and never artifacts.  I tried the same with this 7850 and have had zero accepts at I 16.  My novice tuning hasn't resulted in much either.  

Other GPU benchmarks seem to place the 7850 at about par with other 7850s.  So, I'm not sure if I just have to do special tuning with this powercolor 7850 or if the card is garbage or what?

Help, ideas?

Thanks.

[SpeedDemon13]

What TC are you running? I own a Gigabyte 7850 2GB card and I run my TC at 16000 at -I 18 with no errors hashing at 365khs~370khs.

[Infectiphibian]

The only time I have had artifacts was when the card was defective. Setting issues have only caused me to have freezing/crashing problems.

[atp1916]

You are missing critical flags.

Make your batchfile this:

Code:

setx GPU_MAX_ALLOC_PERCENT 100
cgminer --scrypt -o [removed pool and workers] --thread-concurrency 10241 -I 19 -w 256 -g 1

[EWold]

Thanks, but I haven't messed with that lately, I recall I had issues with whatever values I tried the past on the 6850, so I just gave it up and let cgminer pick out those values.  I will try setting mine at 16000 like yourself.  But I also thought, might be wrong, that it was a multiple of the shaders, a low number something like 4 times.

Thanks.


Update:

[2014-04-04 12:51:33] Started cgminer 3.7.2
[2014-04-04 12:51:33] Started cgminer 3.7.2
[2014-04-04 12:51:33] Probing for an alive pool
[2014-04-04 12:51:34] Pool 0 difficulty changed to 32
[2014-04-04 12:51:40] Maximum buffer memory device 0 supports says 536870912
[2014-04-04 12:51:40] Your scrypt settings come to 1048576000
[2014-04-04 12:51:40] Error -61: clCreateBuffer (padbuffer8), decrease TC or in
rease LG
[2014-04-04 12:51:40] Failed to init GPU thread 0, disabling device 0
[2014-04-04 12:51:40] Restarting the GPU from the menu will not fix this.
[2014-04-04 12:51:40] Try restarting cgminer.
ress enter to continue:

with "--shaders 1024 -I 18 --thread-concurrency 16000"

[EWold]

You are missing critical flags.

Make your batchfile this:

Code:

setx GPU_MAX_ALLOC_PERCENT 100
cgminer --scrypt -o [removed pool and workers] --thread-concurrency 10241 -I 19 -w 256 -g 1

That gets me this.



 [2014-04-04 12:55:03] Started cgminer 3.7.2
 [2014-04-04 12:55:03] Started cgminer 3.7.2
 [2014-04-04 12:55:03] Probing for an alive pool
 [2014-04-04 12:55:03] Pool 0 difficulty changed to 32
 [2014-04-04 12:55:04] Maximum buffer memory device 0 supports says 536870912
 [2014-04-04 12:55:04] Your scrypt settings come to 671154176
 [2014-04-04 12:55:04] Error -61: clCreateBuffer (padbuffer8), decrease TC or in
crease LG
 [2014-04-04 12:55:04] Failed to init GPU thread 0, disabling device 0
 [2014-04-04 12:55:04] Restarting the GPU from the menu will not fix this.
 [2014-04-04 12:55:04] Try restarting cgminer.
Press enter to continue:

[EWold]

-thread-concurrency 4096 -I 16 -w 256 -g 1

results in this.

 cgminer version 3.7.2 - Started: [2014-04-04 13:37:00]
------------------------------------------------------------------------------
 (5s):310.1K (avg):300.1Kh/s | A:64  R:0  HW:499  WU:18.1/m
 ST: 2  SS: 0  NB: 2  LW: 18  GF: 0  RF: 0
 Connected to crypto-coin-pool.com diff 16 with stratum as user EC488.CG6850
 Block: 27fef98f...  Diff:5.75K  Started: [13:38:48]  Best share: 116
------------------------------------------------------------------------------
 [P]ool management [G]PU management [ S ]ettings [D]isplay options [Q]uit
 GPU 0:  53.9C 1923RPM | 299.9K/300.1Kh/s | A:64 R:0 HW:505 WU:18.1/m I:16
------------------------------------------------------------------------------

 [2014-04-04 13:36:59] Started cgminer 3.7.2
 [2014-04-04 13:36:59] Probing for an alive pool
 [2014-04-04 13:37:00] Pool 0 difficulty changed to 32
 [2014-04-04 13:37:00] Network diff set to 5.75K
 [2014-04-04 13:37:44] Pool 0 difficulty changed to 16
 [2014-04-04 13:37:44] Accepted 07fdf9c8 Diff 32/32 GPU 0
 [2014-04-04 13:37:48] Accepted 0ab0f6e9 Diff 24/16 GPU 0
 [2014-04-04 13:38:29] Accepted 02354146 Diff 116/16 GPU 0
 [2014-04-04 13:38:48] Stratum from pool 0 detected new block

[pr0d1gy]

Is this your normal computer you use for mining and web browsing, etc? Or a mining rig? If its a rig, I'd say use bamt... Dead simple, can't go wrong, especially with 7xxx & R9 cards

[EWold]

It is also used for gaming, and browsing like this.

Thanks.