Topic: 7970 + cgminer + Litecoin (Read 27269 times)

If I open a browser (in typing this) I saw the hash rate drop to 622khash/s, so I bumped the memory a little to 1440Mhz and the speed came back up into the 640khash/s range, which I'm happy with as long as I don't have any more lockups.

Ckolivas said that LTC is very timing sensitive, so a lower clock might bring a lot of the internal latencies into sync for a more efficient flow, where a high clock end up causing those minute latencies to stack up on top of each other, slowing everything down.

I've always heard that hitting good numbers mining LTC was a lot of playing around and now I know everybody was right. 

I think I may be able to do better but following everyone's advice I played around with mem clocks and settled on 1.6Ghz, engine running at 1Ghz and I was getting around 540khash/s.  I did the calculation on that and then set my engine down to 965 in CCC and my hashes instantly popped up to 634khash/s average.  No idea... I have no idea why the engine running slower would make it hash faster, I'm sure google would turn up something if I really wanted to know.

I'm going to continue playing around to see if I can tweak any more speed out of it.  Thanks guys!!

I tried setting this, 1375 *.605 = 831Mhz on the engine and my hashes dropped to about 420khash/s, re-upped to 1Ghz and it's hashing at somewhere between 480-500kh/s. 

I tried setting this, 1375 *.605 = 831Mhz on the engine and my hashes dropped to about 420khash/s, re-upped to 1Ghz and it's hashing at somewhere between 480-500kh/s. 

Set your memory clock as high as you can get it without crashing, set your core clock at (memory clock * 0.605).

TUNING AN AMD RADEON 7970
Example tuning a 7970 for Scrypt mining:

On linux run this command:
export GPU_MAX_ALLOC_PERCENT=100
or on windows this:
setx GPU_MAX_ALLOC_PERCENT 100
in the same console/bash/dos prompt/bat file/whatever you want to call it,
before running cgminer.

Anyone getting good hashrates running a 7970 + cgminer + Litecoin?

Ive been having nothing but trouble trying to get consistant hashing over 550kh/s. I can get 650-700 for 20 minutes and then i get drivers crashing. Windows 7 64bit. Temps are below 80C on the GPU and below 90C on the VRM. Ive run furmark for an hour straight to rule out it being a bad card. Ive tried many different driver setups, 2 fresh installs.

This might have something to do with it...
http://support.amd.com/us/kbarticles/Pages/737-27116RadeonSeries-ATIKMDAGhasstoppedrespondingerrormessages.aspx

Please list the catalyst version you are running, amd app sdk version, and your command line for cgminer + hashrate.

Im willing to pay in litecoin for a consistant 700kh/s.

TUNING AN AMD RADEON 7970
Example tuning a 7970 for Scrypt mining:

On linux run this command:
export GPU_MAX_ALLOC_PERCENT=100
or on windows this:
setx GPU_MAX_ALLOC_PERCENT 100
in the same console/bash/dos prompt/bat file/whatever you want to call it,
before running cgminer.

First, find the highest thread concurrency that you can start it at. They should
all start at 8192 but some will go up to 3 times that. Don't go too high on the
intensity while testing and don't change gpu threads. If you cannot go above
8192, don't fret as you can still get a high hashrate.

Delete any .bin files so you're starting from scratch and see what bins get
generated.

First try without any thread concurrency or even shaders, as cgminer will try to
find an optimal value
cgminer -I 13

If that starts mining, see what bin was generated, it is likely the largest
meaningful TC you can set.
Starting it on mine I get:
scrypt130302Tahitiglg2tc22392w64l8.bin

See tc22392 that's telling you what thread concurrency it was. It should start
without TC parameters, but you never know. So if it doesn't, start with
--thread-concurrency 8192 and add 2048 to it at a time till you find the highest
value it will start successfully at.

Then start overclocking the eyeballs off your memory, as 7970s are exquisitely
sensitive to memory speed and amazingly overclockable but please make sure it
keeps adequately cooled with --auto-fan! Do it while it's running from the GPU
menu. Go up by 25 at a time every 30 seconds or so until your GPU crashes. Then
reboot and start it 25 lower as a rough start. Mine runs stable at 1900 memory
without overvolting. Overvolting is the only thing that can actually damage your
GPU so I wouldn't recommend it at all.

Then once you find the maximum memory clock speed, you need to find the sweet
spot engine clock speed that matches it. It's a fine line where one more MHz
will make the hashrate drop by 20%. It's somewhere in the .57 - 0.6 ratio range.
Start your engine clock speed at half your memory clock speed and then increase
it by 5 at a time. The hashrate should climb a little each rise in engine speed
and then suddenly drop above a certain value. Decrease it by 1 then until you
find it climbs dramatically. If your engine clock speed cannot get that high
without crashing the GPU, you will have to use a lower memclock.

Then, and only then, bother trying to increase intensity further.

My final settings were:
--gpu-engine 1141  --gpu-memclock 1875 -I 20
for a hashrate of 745kH.

Note I did not bother setting a thread concurrency. Once you have the magic
endpoint, look at what tc was chosen by the bin file generated and then hard
code that in next time (eg --thread-concurrency 22392) as slight changes in
thread concurrency will happen every time if you don't specify one, and the tc
to clock ratios are critical!

Good luck, and if this doesn't work for you, well same old magic discussion
applies, I cannot debug every hardware combo out there.

Your numbers will be your numbers depending on your hardware combination and OS,
so don't expect to get exactly the same results!