Help me tweak my 280x DC2T-3GD5's!

[dragonmike]

Hello folks

Just got a rig built with six of the cards mentioned in the title (4 are running at the moment due to a failing PSU... will replace and connect the last two shortly).

I'm just wondering why some of the reported hashrates on https://litecoin.info/Mining_hardware_comparison vary so much between cards although many people are using very similar clock and mem rates (and the bog standard "-I 13 -g2 -w 256 --thread-concurrency 8192" settings most people seem to use)...

I see people reporting between 570 and 750+ Kh/s rates without apparent differences in the parameters... Most even use the same catalyst driver version!

So I'm wondering what makes the difference, really.

I started mining on the middlecoin switching pool and hashrate for my card's stock settings (1070/1600) were around 650 Kh/s.

I'm using latest Cats & App SDK. Win8.1.
My .bat file also starts with the usual setx GPU_MAX_ALLOC_PERCENT 100 and setx GPU_USE_SYNC_OBJECTS 1 commands.

Any ideas on what I could do to improve this? What am I not seeing?

Thanks!

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[dragonmike]

Just hit me that I didn't install any drivers in Windows for my MoBo... would I even need to and would that make any difference for mining?

[dragonmike]

Anyone? :-I

[maardein]

Is your GPU usage really 100% when you look at it in GPU-z?

Also try a higher intensity, 13 is quite low.

[sammart57]

I ran into this problem with mine.. as far as I can tell the stock settings everyone claims they're getting 750+ with that card are bs.
I have tried several versions of sdk, several versions of catalyst drivers, and a ton of cgminer settings.. the best I can do is just about 700 with
-I 20 -g2 -w 256 --thread-concurrency 24000

I think I also have the cards around 1070/1250, bumping it up didn't do anything for me, I would lose kh going much higher.

There are 2 versions of the card tho, so maybe the 750+ people are using the non v2 version?
the non v2 is the one pictured in your link, it's a 2 slot design, much thinner and uses less power according to reports.

the v2 version is linked at the bottom of that page..

[Badegakk]

Hi i am running two of those Asus R9 280x DCII TOP cards. NON v2.
i am using thread-concurrency 8192 with engine at 1134, memclock 1800 and powertuner at +20.
One is running at 770, the other at 790.

It is cold here (Norway) but i don't need any additional heating in the house

https://dl.dropboxusercontent.com/u/17952252/Skjermbilde%202014-01-15%20kl.%2022.39.21.png

EDIT: Intensity 13

[crazyates]

I don't have your specific card, but scrypt is very sensitive to Core/RAM speed changes.

I'm also using the pretty standard 8192 TC, 2 threads, I:13, and 256 worksize.

@ 1025/1500, I get ~710Kh/s. @ 1025/1505, I get 500Kh/s.

They don't like to mine on anything above 1500MHz RAM, unless it's crazy high. The only other time I can get >700Kh/s is @ 1044/1800, which isn't exactly stable.

Once You set the RAM @ 1500, try any core clocks in the 1020-1060 range. I get 711Kh/s @ 1020, and peak upwards of 730Kh/s @ 1060, but it drops off to the low 600Kh/s range once I go over 1060.

[dragonmike]

All very good insights, thanks!
I installed the chipset drivers last night and that bumped speeds up to 700. So that was good. However, playing around with clock speeds indeed sometimes increased hash rates but sometimes actually didn't do anything at all. Seems to be a tricky balancing act. Leaving gpu clocks at 1070 but increasing ram clocks to 1700 (from 1600) seemed to have made quite a difference. I'm going to have to try down-clocking it to 1500 but that does feel quite weird heh!

Also, I've done that while connecting to a switching pool, it probably would make sense solo-mining when tweaking as you'd want to rule out pool-connection effects...

Lastly, I just heard I should set the priority to above normal... still need to try that out tonight.

Btw I do use the newer, NON-v2 version.

[dragonmike]

Also, would you use powertune at all? If the aim is to keep voltage low, and temps below a given threshold I suppose using powertune kinda defeats the purpose no?

[goldbars]

what powertune setting are people using for the 280x? what does - and + powertune do?

[nnay_th]

All very good insights, thanks!
I installed the chipset drivers last night and that bumped speeds up to 700. So that was good. However, playing around with clock speeds indeed sometimes increased hash rates but sometimes actually didn't do anything at all. Seems to be a tricky balancing act. Leaving gpu clocks at 1070 but increasing ram clocks to 1700 (from 1600) seemed to have made quite a difference. I'm going to have to try down-clocking it to 1500 but that does feel quite weird heh!

Also, I've done that while connecting to a switching pool, it probably would make sense solo-mining when tweaking as you'd want to rule out pool-connection effects...

Lastly, I just heard I should set the priority to above normal... still need to try that out tonight.

Btw I do use the newer, NON-v2 version.

Hey mate,

I have the exact same cards. I have between 740 kh/s (4 cards on one MB) and 750 kh/s (single card on motherboard) with those settings:

--scrypt -I 13 -w 256 --thread-concurrency 8192 -g 2 --auto-fan --temp-target 75 --temp-overheat 85 --gpu-engine 1080 --lookup-gap 2 --gpu-memclock 1500 --scan-time 1 --queue 0

Hope it helps

[crazyates]

Also, would you use powertune at all? If the aim is to keep voltage low, and temps below a given threshold I suppose using powertune kinda defeats the purpose no?

I do both. I undervolt to 1.01V, and then set Powertune to +20. Keeps temps down, and lower power consumption, but basically tells the cards to use as much power as needed to get max hashrate.

[dragonmike]

Little update for whomever is interested... I've managed to get 5 (out of 6) cards hashing so far. Hashrate = 756Kh/s stable @ 1.170V (will try to go lower at a later stage).

I have the following settings (only showing relevant ones):

-I 13 -w 256 --thread-concurrency 8192 -g 2 --gpu-engine 1085 --gpu-memclock 1500
I left lookup gap out completely. I think it only makes sense if you want to enable higher TC and use only one GPU thread. Might give these combos a try at some point later but for now I'm happy with my hashrate! Funny how downclocking the mem by 100MHz actually increased hashrate massively :-D

Now next problem = getting the 6th GPU to get recognised in Windows... hmmm.