7870 performance

[ltcde4]

What sort of hash rate should I expect from 2x 7870s running cgminer on xubuntu?

Thx.

[eraserius]

You should expect Around 800 without too much overclocking, but this is a rough estimate, since its it a lot of different versions of this card. If you provide more info I will be able to get more accurate.

[jamesblack]

about 400 m/has 

[eraserius]

about 400 m/has 

First he ask how much from 2x 7870 and you divided 800/2 = 400 cool story bro 

[ltcde4]

400 each is what I thought... But for some reason I can't get mine to run over 305/310... I'm using cgminer 3.1 on xubuntu... The actual cards are Gigabyte HD7870 1100 Overclock 2GB RAM... I've tried messing around a bit with the parameters, but not getting very far. The cards run faster doing litecoins... About 350KH/s.

Any guidance would be awesome!

Thanks!

[algorithmic]

400 each is what I thought... But for some reason I can't get mine to run over 305/310... I'm using cgminer 3.1 on xubuntu... The actual cards are Gigabyte HD7870 1100 Overclock 2GB RAM... I've tried messing around a bit with the parameters, but not getting very far. The cards run faster doing litecoins... About 350KH/s.

I am seeing about 410kH/s with the same card.
Flags are: --scrypt --thread-concurrency 14208  --intensity 18
All other parameters use default values.
The system is running Fedora 18 with 4GB memory.
cgminer 2.11.4

[m14yen]

i have 3 of the newer 7870 tahiti le's. each overclock to ~1200mhz and mine at 500-520Mh/s
this is in windows running bitminter.

anyone thinking of getting a 7870, go for the sapphire one overclocks higher than the rest.
the xfx one is ok, runs slightly warmer than the sapphire (both have 2 fans)
the powercolor one is the worst fan usage is crazy fast/slow/fast/slow runs much hotter.

[ilostcoins]

I only get about 300kH/s scrypt performance with 7870, partly because I don't want to use high intensity settings.

My main settings are
-I 12 --thread-concurrency 8192 -w 256 -g 2 --gpu-engine 900

There is some discussion in the link below about possible benefits from raising memory upper bound, overclocking memory and underclocking GPU.
http://forum.litecoin.net/index.php/topic,1420.0.html

[ilostcoins]

A strange thing I noticed is if I load a few other programs (web browser etc.) before running cgminer, there seems to be a small but noticeable gain, like +10kH/s. I seem to get a bit less performance if I run cgminer from a relatively clean state. Strange.

[ltcde4]

I am seeing about 410kH/s with the same card.
Flags are: --scrypt --thread-concurrency 14208  --intensity 18
All other parameters use default values.
The system is running Fedora 18 with 4GB memory.
cgminer 2.11.4

Tried these settings with litecoins, and besides having to tweak the thread concurrency down to 8000 to get cgminer to start, I'm getting right around 400 on each card! Thanks!

Any ideas how to increase my hash rate mining BTCs?

Thanks again for the input so far!

[jamesblack]

mmmhh i think 700 m /has....

[sexcoyote]

with my 7950 i have 450 m/has , i think you have 350 !

[morinaga]

800

[algorithmic]

I am seeing about 410kH/s with the same card.
Flags are: --scrypt --thread-concurrency 14208  --intensity 18
All other parameters use default values.
The system is running Fedora 18 with 4GB memory.
cgminer 2.11.4

Tried these settings with litecoins, and besides having to tweak the thread concurrency down to 8000 to get cgminer to start, I'm getting right around 400 on each card! Thanks!

After sending that reply I updated to cgminer 3.1 and also found it necessary reduce thread concurrency to run.  I couldn't find suitable values to get back to 410kH/s, so for now have reverted to 2.11.4.

Any ideas how to increase my hash rate mining BTCs?

Thanks again for the input so far!

Glad to be of help. Sorry, it has been a while and I no longer have the settings I used for bitcoin. I think I was getting around 440MH/s with very minimal tweaking.

[JungleBook]

up to 1400 sha256 1200 scypte

[Bitshire_Hathaway]

400

[r3wt]

whoa, have you checked your settings? my 16 card setup is pulling 3.1 petaflops

[ltcde4]

Grabbed bfgminer, and while it'll do just over 400khash/s, its very unstable! Crashes the machine hard within a few hours... Considering installing Windows and messing with guiminer... seems to do better then the same mining kernels under Linux!

For the LTC miners, are you going solo or in a pool? Do you feel its more profitable to mine LTC at this point?

TIA!

[algorithmic]

For the LTC miners, are you going solo or in a pool?

Pool - ltcmine.ru is pretty good.

Do you feel its more profitable to mine LTC at this point?

There is a convenient mining calculator at http://dustcoin.com/mining that compares the profitability of BTC and the major alt currencies using cost of power, hash rates, current difficulty levels and exchange rates.  LTC and BTC seem pretty close right now for the Gigabyte 7870.