600Kh from an R9 280x

[miztaziggy]

So I am running 5 x R9 280x in one system. All cards are brand new Sapphire Vapor X.

4 of them are plugged into the board with 1x risers and are hashing at 700-740 with TC 8192 clocks 1070/1500 (all the other usual settings g 2, w 256 etc).

The last card is plugged into the second PCIE x16 slot with a x16 -> x16 riser. In Trixx it is detected as 4x PCIE which is correct.

Slots on the board:
1x PCIE
16x PCIE
1x PCIE
1x PCIE
16x PCIE (running at 4x)

The card on the x16 riser only runs at approx 600 KH with those settings.

If I lower the TC to 8100 then it jumps up and almost matches the others, but it gives HW errors.

If I lower the clocks to 1050/1500 it goes up slightly. If I lower further to 1030/1500 it goes up a little more. Maxxes out at approx 650 KH.


Question is then what settings can I try to increase the hash of that card?
I can't lower the TC. If I raise the TC it makes no difference.
I have undervolted to 1.1 and it is still the same.

Maybe I have a bad card?

[cryptocleaner]

try 1044/1500

[vm1990]

if you can test it in another rig on its own. it could also be a normal card which isnt quite as good as the other. no gpus are the same

[breakbeater]

What OS are you using?
Win 7 make problems with more than 4 Cards.

[miztaziggy]

Yeah I think I will test it on its own, see what happens

I am using Win 8.1