what are your settings rascal?
if i clock my memory over 1350 it just crashes the system?
1139/1500 - core/memif i clock my memory over 1350 it just crashes the system?
tc >22k
i 19
lg 2
Topic: 7870 saphire - getting 430mh/ash on sha-256, but only 280khs on scrypt? (Read 1458 times)
May 09, 2013, 04:43:39 AM
tc >22k
i 19
lg 2
May 09, 2013, 04:36:38 AM
Scrypt is very dependent on memory speed so the core/memery ratio really is the most important criteria. Of course the best way to find the ideal ratio is if someone has already done the work and has found posted it somewhere!
Generally, the core should be roughly 0.7 the speed of the memory. So with a core of 1000MHz that means ~1428MHz. On 7950s I've found these rations to work 1022/1244 or 1100/1500.
For experimenting with rations, I found cgminer the best since unlike when using the GUI front-end (GUIMiner - which anyway uses cgminer), you can change the GPU settings dynamically in the program without having to disconnect. So, just hit etc., change the settings give them a few minutes to get an idea if they work. Repeat until you get your optimal.
BTW, when a SHA-256 coin is close in profitability to scrypt, it makes sense to mine SHA-256 since once you underclock the memory SHA-256 uses a fair bit less energy.
Generally, the core should be roughly 0.7 the speed of the memory. So with a core of 1000MHz that means ~1428MHz. On 7950s I've found these rations to work 1022/1244 or 1100/1500.
For experimenting with rations, I found cgminer the best since unlike when using the GUI front-end (GUIMiner - which anyway uses cgminer), you can change the GPU settings dynamically in the program without having to disconnect. So, just hit
BTW, when a SHA-256 coin is close in profitability to scrypt, it makes sense to mine SHA-256 since once you underclock the memory SHA-256 uses a fair bit less energy.
May 09, 2013, 04:03:54 AM
good idea 
May 09, 2013, 03:46:35 AM
setx GPU_MAX_ALLOC_PERCENT 100
on /cmd
on /cmd
May 09, 2013, 03:37:46 AM
Here somesetting u could try....or maybe just consider some parameters....
https://github.com/litecoin-project/litecoin/wiki/Mining-hardware-comparison#wiki-ATI_AMD_GPUs
https://github.com/litecoin-project/litecoin/wiki/Mining-hardware-comparison#wiki-ATI_AMD_GPUs
May 09, 2013, 03:26:39 AM
U could try to underclock a little so u have not to go so high with mem
May 09, 2013, 03:22:14 AM
yeah im using msi afterburn, and doing small increments but over 1350 mem it starts to crash
1500 mem is a huge increase!
1500 mem is a huge increase!
May 09, 2013, 03:15:34 AM
I haven't a 7870 but for scrypt mining u have to find the right value for memory.....for sha256 u can downclock memory for scrypt u have to overclock it in the right range....for example on my 7970 i use these settings:
core: 985 mem:1410
core: 1000 mem:1475
u have to do some small change in memory wait 30 second and check the hashrate.
If u are on windows use MSI afterburner for do this.
core: 985 mem:1410
core: 1000 mem:1475
u have to do some small change in memory wait 30 second and check the hashrate.
If u are on windows use MSI afterburner for do this.
May 09, 2013, 03:05:50 AM
what are your settings rascal?
if i clock my memory over 1350 it just crashes the system?
if i clock my memory over 1350 it just crashes the system?
May 09, 2013, 02:59:05 AM
i got sapphire 7970 vapor-x which only got 520Khs (700+ for normal 7970 card) ; 720++ on sha-256
Then after flash sapphire 7970 (not vapor) rom , i got 750++
Then after flash sapphire 7970 (not vapor) rom , i got 750++
May 08, 2013, 10:49:09 PM
1) Read the manual (scrypt-readme)
2) Profit http://img90.imageshack.us/img90/1549/cgminer7870470.jpg
2) Profit http://img90.imageshack.us/img90/1549/cgminer7870470.jpg
May 08, 2013, 10:09:34 PM
unfortunately didnt have any effect :/ yeah if you could let me know tomorrow that would be awesome, just sha-256ing in the meantime 
May 08, 2013, 09:57:40 PM
oh if you could help me with the flashing that would be great.
currently best stable i can get id --shaders 1280 --intensity 12 --worksize 256 -g 1
if i put intenstiy at 20 i get about another 15khash but obviously cant use the pc at the same time
currently best stable i can get id --shaders 1280 --intensity 12 --worksize 256 -g 1
if i put intenstiy at 20 i get about another 15khash but obviously cant use the pc at the same time
Try intensity 13 -g 1, then I 13 -g2 and I 12 -g 2 quickly.
I'll have to help you out with the flashing tomorrow, it's 4am over here and i gotta go sleep soon lol
May 08, 2013, 09:36:52 PM
oh if you could help me with the flashing that would be great.
currently best stable i can get id --shaders 1280 --intensity 12 --worksize 256 -g 1
if i put intenstiy at 20 i get about another 15khash but obviously cant use the pc at the same time
currently best stable i can get id --shaders 1280 --intensity 12 --worksize 256 -g 1
if i put intenstiy at 20 i get about another 15khash but obviously cant use the pc at the same time
May 08, 2013, 09:24:15 PM
sorry its a ghz edition
Ok, you most likely have the same problem i had - Where basically the card is fine on sha256, but scrypt it underperforms for no good reason.
The solution is to flash the bios to a non Ghz edition of the card.
I've only done it with the 7970 vapor-x, and i know it 100% works for that card... but there is a chance you could brick your card, unless you have another pc or another card you can use in the unlikely event the new bios didnt work, so you could just flash back to the old one.
It is probably completely fine, but i just wanted to warn you there is the very small chance something could go wrong.
If you want to go ahead and you need help flashing the bios, let me know
Edit - what setting are you currently using, i.e intensity, -g, thread concurrency etc
May 08, 2013, 09:20:57 PM
sorry its a ghz edition
May 08, 2013, 09:16:05 PM
Is it just Sapphire or is it Ghz edition, OC edition, Vapor-x..?
May 08, 2013, 09:14:45 PM
hi, its a saphire, with a pitcairn GPU
May 08, 2013, 08:35:59 PM
What is the exact make/model of the card you are using?
May 08, 2013, 08:32:47 PM
Any idea why so low? system is a i5 3570 4gb ram and have tried to tweak msi afterburn up a bit but no way its stable after 310~khash
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