Bitcoin Forum

hey guys... i have three 5870s running at 950/900 @ stock volts, but they only get a max of 320MHash (310-315 average)... my temps are around 80-85C @ 70% fan speed... i was wondering if anybody knows why they are running at such low hash rates, because when i check the wiki it has stock clocks getting better hash rates than this... any help is welcome

thank you in advance

EDIT: these cards are non-refrence if that makes a difference with hash rate

what miner are you using with what flags on what os

Temps are a bit high.......but try the flags -v or -v 2  in association with -w128 and F3 on the other cards not attached to your monitor.I would also like to mention trying to downclock the memory to 300 instead to get lower temps in order for higher clocks if possible.You can check other mining combinations here (https://en.bitcoin.it/wiki/Mining_hardware_comparison) for a good comparison.


If you get everything to work I'd also suggest going here by using the modified files here using the appropriate intructions from each thread whether from Phat K (https://bitcointalk.org/index.php?topic=7964.0) or Diapolo (https://bitcointalk.org/index.php?topic=25135.0).

i am running poclbm on 32it xp pro... i just realized that i didnt have any flags, but even with "-f 0 -v -w128" i only average 350mhash... but when i start mining it will start at 400+ per card and then lower to the 350... unfortunately temps that high are hard to avoid because the ambients recently have been 95f+... however, they are not downclocking because of heat, so idk what causes then to drop for 400 to 350 mhash

EDIT: also, what program do you use to let you get your memory down into the 300s? i have only found ones that let me get around 600

I had 3 5870's in a HAF-X, too, and they were maxing around 70°C with 70-80% fan speed... you should definitely lower the mem clock to 300 Mhz and raise the fan speed to 80% and see if this helps. And as already mentioned, use appropriate flags in your miner :)

Apparently MSI afterburner or TRIXX would be the best application for Multi-GPU over and underclocking.What it starts out at isn't really important considering I have a 6950 that starts out @ 440 Mh/s but settles around 353-358.Most videocards also showcase in Celsius not Fahrenheit and CAN dynamicallly shutdown or have other protective features from overheat as they all have a threshold.

You never mentioned your driver variants either as perhaps you could have the 100% driver bug as well limiting performance under XP.Catalyst 11.7 or later is not recommended.....but the 11.6B's are the best for XP I find.

My card does display temps in c... And it is not downclocking because of heat... Also, I am using 11.6b... I will try trixx to get lower clocks (msi stops at 600)... What flags do you guys use for 5870s? The max I can seem to get is around 350 when I see many others getting 400+... And I'm also getting a little higher (360 or so) on my eah5850 (non-ref)... I don't see any reason for it to get higher hash with the same flags

This is curious to me, I'm running a single 5870 940/425, and its pulling in 395 Mhash with -v -w128 -f70 flags (I tend to watch movies/tv while mining).

Its obviously not a power issue, but is there any kind of performance penalty from running in crossfire?

There shouldn't be at all, but I'm not running x fire anyways... The 780i doesn't support it so I run them separately... I will try those flags, but I just can't seem to get these guys over the 350 mark

yes crossfire does carry a performance penalty for bitcoin mining but if you use said rig for games as well don't worry about it. i've been able to run my 5870 at 400+(415 usually)(clocks 1000/500 dosen't want to run at 400 or lower) just using -v -w256 running poclbm using gui miner on windows 7 x64. I would hazzard a guess xp is probably going to be a bit slower for bitcoin mining since support for open cl isn't native to the operating system but not beyond a 1-2% diffrence with identical cards.

your cards are bad.  just give them to me instead.

lol... ship me 3 ref 5870s and you have a deal :p

Bump... Any other advice or things to try?