Author Topic: Low hash rate on 7970  (Read 22084 times)

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Offline raptorxrxTopic starter

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Low hash rate on 7970
« on: July 21, 2013, 08:45:30 PM »
As a previous Bitcoin miner moving to Litecoin, I have to say, many things confuse me. Although googling has fixed many of my problems, I still can't get my hash rate up.  Why can I average 690 MH/s on Bitcoin, but can barely get 525 KH/s on Litecoin? By my research, a 7970 should at least get 600 KH/s at stock settings.


Any advice would be appreciated.


« Last Edit: July 21, 2013, 08:57:48 PM by raptorxrx »


Offline grapemon1611

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Re: Low hash rate on 7970
« Reply #1 on: July 27, 2013, 04:18:01 PM »
I too had a shock when I moved from BTC to LTC mining.  When I looked at the average Pool speed for LTC and then my average hash rate for BTC I thought I was going to mine 50 LTC a day!

However, that isn't the case as you have already discovered.  It has to do with the way your miner actually produces shares towards each block.  BTC uses a completely different algorithm than LTC.  BTC uses sha256 algoithm and LTC uses scrypt (which is why you have to have a different mining software).  I'm using 7870's and my hash rate dropped from 600Mh/s per card to 270Kh/s going from BTC to LTC.

Now, to address what your card should be doing verses what it actually does.  Using the LiteCoin Mining Hardware Comparison [nofollow]the 7870 should be hashing out 350Kh/s.  However  anytime I attempt to actually use the settings suggested my machine reboots after various periods of time.  I will say that the motherboard seems to affect the performance.  My cards in AMD based boards produce more hashes than my Intel based ones. Also, the amount of RAM both on the GPU (on the 7870 there are 1GB, 2GB, and 3GB versions) and the system RAM.  Other factors include cooling of the system and the PSU.  I got a significant boost to performance when I moved to open air cases and 1500 Watt gaming PSU's.

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Offline mxc0bbn

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Re: Low hash rate on 7970
« Reply #2 on: July 30, 2013, 07:58:43 AM »
I never got more than 570 out of my 7970 so I decided I need to stick to 7950s where I can get between 630-670 out of them with almost no tuning.

I would definitely go to a 7950...
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Offline EmuneLTK

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Re: Low hash rate on 7970
« Reply #3 on: July 30, 2013, 09:21:18 AM »
The best answer I have found when getting stuck on that 550 mark is doing a BIOS flash. I found this worked for 2 of my 7970 GPU's one being a Gigabyte and another Saphire. This thread really helped me :


newbielink:https://forum.litecoin.net/index.php/topic,2963.0.html [nonactive]


but also read my thread that eventually won the race and am now getting 770 each with 1100/1500 speeds.


newbielink:https://forum.litecoin.net/index.php/topic,4408.30.html [nonactive]

Offline shadizzle

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Re: Low hash rate on 7970
« Reply #4 on: October 30, 2013, 07:33:04 PM »
I have both a 7970 and a 7950,


For some reason the 7950 is much faster than my 7970


7970- 375khash/s  (vistiontek)
7950- 495khash/s  (msi)
6870- 278kash/s (powercolor)
Using GUIminer- scrypt alpha, ive played with the intensity, threads, etc.. no change for some reason




 

Incredibly low hash rate :(

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