OS X 5770 speeds

Davereplicant

Hello,
As mentioned in another post I have two 5770’s running in cgminer -w64 -i 16 and each card is hashing at 60-80 khs. This seems a little slow. Any higher on the intensity and the machine is unusable.
I have another machine, a pc running a single 5860 (I think?) and this is running over 300.

Should I investigate this further and would anyone have any suggestions?

This mac rig used to mine btc faster than the pc.

Thanks in advance.

Aldanga

That is low. Try changing your worksize to 256.

Davereplicant

Thank you sir, I thought so too.
I know mining btc under OS X the open cl drivers didn’t like a work size other than 64 but under scrypt maybe this doesn’t apply.

I’ll see what happens.
Thanks

Aldanga

I can’t speak for worksize implications in OS X as I don’t have a functioning install to test. You might be correct about that. If it holds true, someone who mines on OS X will likely need to assist you instead.

Davereplicant

In the interests of science I shall try at my earliest opportunity.
Cheers

Try running cgminer --benchmark and see what u get, it should be a good score. Mining BTC seems to work fine under OSX but scrypt is really bad for some reason.

If you run the same cgminer --benchmark --scrypt you will get ~10kh/s or less, tweaking gets it upto a max of 100 or so on the 5770 which is still bad, I get about 150mh/s on my debian server using a 5770.

I am trying with a 7850 on OSX (Yes hackintosh). On linux I can get over 300 kh/s just adjusting the -I setting.

On OSX I get massive HW error setting the I over 11. At best I can get about 60kh/s

It seems like something is really broken with the scrypt implementation on OSX.