Overclocking Supposed to Help Mining, Right?

[DirkaFat]

Whenever I overclock my 7970, the k/hs drops considerably (600 to 400, or something like that). Temperature is 75 C and the overclock is 1050/1425 at 1.175v, which I've confirmed to be stable.

 

 

 

 

 

 

[LapX]

If it's not stable theres a chance it could do bad calculations, maybe that's why you got reduced speed. I am no expert though.

[Andi]

if you overclock and your rate and or fps goes down you overclock isn't stable, it's possible to clock a card higher and get lower results

[DirkaFat]

if you overclock and your rate and or fps goes down you overclock isn't stable, it's possible to clock a card higher and get lower results

The thing is, I've tried the overclock mentioned above, but I've also tried lowering the overclock in increments (Such as 1000/1400, 975/1390, etc. until I return to stock speeds)

[RuecanOnRails]

No, overclocking does not = higher hashrate.

 

You need a balanced set up. A ratio between Core/Mem and a thread concurrency which works well with that ratio. Taken from the CGminer scrypt readme file. This short tuning guide focuses on steps which should be taken to find a max hashrate. I would recommend using -g 2 -i 13. two threads and a lower intensity will likely see the card reach it's max a little easier.

---TUNING AN AMD RADEON 7970Example tuning a 7970 for Scrypt mining:On linux run this command:export GPU_MAX_ALLOC_PERCENT=100or on windows this:setx GPU_MAX_ALLOC_PERCENT 100in 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 shouldall start at 8192 but some will go up to 3 times that. Don't go too high on theintensity while testing and don't change gpu threads. If you cannot go above8192, 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 getgenerated.First try without any thread concurrency or even shaders, as cgminer will try tofind an optimal valuecgminer -I 13If that starts mining, see what bin was generated, it is likely the largestmeaningful TC you can set.Starting it on mine I get:scrypt130302Tahitiglg2tc22392w64l8.binSee tc22392 that's telling you what thread concurrency it was. It should startwithout 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 highestvalue it will start successfully at.Then start overclocking the eyeballs off your memory, as 7970s are exquisitelysensitive to memory speed and amazingly overclockable but please make sure itkeeps adequately cooled with --auto-fan! Do it while it's running from the GPUmenu. Go up by 25 at a time every 30 seconds or so until your GPU crashes. Thenreboot and start it 25 lower as a rough start. Mine runs stable at 1900 memorywithout overvolting. Overvolting is the only thing that can actually damage yourGPU so I wouldn't recommend it at all.Then once you find the maximum memory clock speed, you need to find the sweetspot engine clock speed that matches it. It's a fine line where one more MHzwill 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 increaseit by 5 at a time. The hashrate should climb a little each rise in engine speedand then suddenly drop above a certain value. Decrease it by 1 then until youfind it climbs dramatically. If your engine clock speed cannot get that highwithout 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 20for a hashrate of 745kH.Note I did not bother setting a thread concurrency. Once you have the magicendpoint, look at what tc was chosen by the bin file generated and then hardcode that in next time (eg --thread-concurrency 22392) as slight changes inthread concurrency will happen every time if you don't specify one, and the tcto clock ratios are critical!Good luck, and if this doesn't work for you, well same old magic discussionapplies, 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!

[peachtopus]

when i over clock my 5770s on one i get an extra 11KH/s
 and when i over clock the other i get a whole extra 40KH/s

 

so yes it can help