how to acheive optimal cgminer performance with Radeon 7870, DC2-2GD5-V2

[Quenouille79]

Hi,

My hashrate with my Radeon 7870, DC2-2GD5-V2 is around 345K

I saw on this site https://litecoin.info/Mining_hardware_comparison, that I should be able to pull higher hashrate with this card, well at least around 375-380K. I tried everything and can,t get more than 345K

Basically, i'm using simple parameters:  -I 12 -g 2 -w 256 --thread-concurrency 8192


I tried what they propose on hardware wiki: https://litecoin.info/Mining_hardware_comparison, but I actually got worse performance by far using what they propose there.

I tried to change the core clock speed and stuff like that, but it get worst also.


Anybody with this card knows what settings are necessary to achieve a higher hashrate?


Thanks in advance!

[Wipeout2097]

 Try -I 20 -g 1  --thread-concurrency 15232

[Quenouille79]

Try -I 20 -g 1  --thread-concurrency 15232

thnx for helping, i tried that but i only get 215K max with that.

[Wipeout2097]

Ok, I deleted this previously, posting again...

Scrypt is very sensitive to vram timings. The 7870's have lot of variation regarding ram suppliers from good Hynix to cheap Elpida and furthermore the bios programs those timings in a weird way. They are the equivalent of the usual 9-9-9-24 you see for system ram (eg. CAS, TRp) that one can tweak on the pc bios. They obviously also exist for video memory, but afaik there isn't a tweaking utility for video.

What you can try is to force flash a bios from a card that gives high hash rate. However if the vrms and ram are incompatible or can't handle the timings, voltages, etc... it will crash and you may even brick the card.

[Quenouille79]

Ok, I deleted this previously, posting again...

Scrypt is very sensitive to vram timings. The 7870's have lot of variation regarding ram suppliers from good Hynix to cheap Elpida and furthermore the bios programs those timings in a weird way. They are the equivalent of the usual 9-9-9-24 you see for system ram (eg. CAS, TRp) that one can tweak on the pc bios. They obviously also exist for video memory, but afaik there isn't a tweaking utility for video.

What you can try is to force flash a bios from a card that gives high hash rate. However if the vrms and ram are incompatible or can't handle the timings, voltages, etc... it will crash and you may even brick the card.

thnx but its too complicated for me i was looking for a simple tweak solution in my cgminer command line, hehehe

[Wipeout2097]

Perhaps your core speed is too high when related with the ram. Append --gpu-engine 800 --gpu-memclock 1400 to your command line, and then try again increasing the --gpu-engine 10 mhz at a time

[Quenouille79]

Perhaps your core speed is too high when related with the ram. Append --gpu-engine 800 --gpu-memclock 1400 to your command line, and then try again increasing the --gpu-engine 10 mhz at a time

I tried but cannot get more than 250K using that method.