Quote from: ma_rine_sa on May 08, 2013, 06:24:22 PM

I have spent over 24 hours smashing my head against the wall trying to figure out why my sapphire 7950 4L simply will not mine, can not connect to servers, produce HW errors.

Same boat here, except it looks like i'm finally getting to a setup that's mining alright. Maybe not perfect, but a lot better than what I was getting.

FYI, here's details of my setup as it was yesterday & now.
I hope someone finds it useful.

FD

2 x 7950 Frozrs - No Crossfire
Win7 64 w/ cgminer 3.1
AMD SDK 2.7
Catalyst 13.4

Yesterday
- AMD 2.8 SDK
- using (very basic - pool authentication only) .bat with cgminer
- anything over intensity 12 produced HW errors. -I 20 literally produced 100s of them in minutes
- Utility rate of about 3 shares a minute
- GPU Temps 80C with fans @ 85%

Today
1. Removed the AMD 2.8, the cgminer readme mentions known issues with this, and installed AMD SDK 2.7.
2. Removed the .BINN files from the cgminer folder, started it using cgminer.exe and entered pool info. The new .BINN file created contains a thread concurrency value, record that. In cgminer use menu then [W] which created a cgminer.conf file.
3. Edited the new cgminer.conf with details... adding a couple then testing, then repeating.
4. Set memory & GPU clock speeds following this guide. https://bitcointalk.org/index.php?topic=175646.0

Things I noticed
a. Any Intensity over 12 causes HW errors and lower Utility rate. So, -I 12 it is.
b. Any Thread Concurrency over 8000 causes the driver to crash. I'm now using 4032 as it was the value cgminer used in step 2.
c. 1600Mhz was stable with 1100Kh/s, but the Utility rate was very low at around 6-7 Shares/m.
--- Setting 1450Mhz dropped the hash rate to 920Kh/s, but the Utility rate rose to around 30 shares/m.
--- Sweet spot for this GPU Clock seems to be 0.672 * Memory Clock. So 974Mhz, this gets me 920kh/s with almost 0 HW errors.
d. GPU Temps now 65C with fans @ 55%

Config:
"thread-concurrency" : "4032,4032"
"lookup-gap" : "1,1"
"intensity" : "12,12"
"vectors" : "1,1"
"worksize" : "256,256"
"kernel" : "scrypt,scrypt"
"scrypt" : true
"shaders" : "1792,1792"
"temp-overheat" : "85,85"
"temp-cutoff" : "90,90"
"temp-target" : "75,75"
"gpu-powertune" : "20,20"
"gpu-fan" : "auto,auto"
"gpu-platform" : "0"
"gpu-threads" : "2"

// Used for CGWatcher
"api-port" : "4028"
"api-listen" : true
"api-allow" : "W:127.0.0.1"