I have tested some more. Release 74 is using more power and heat, so the card trottle and performance is lost.
My test was conducted in a closed case rig with a EVGA superclocked card (2x 6pins power)
but my dev card:
The gigabyte 970oc G1 comes with 1x8 pin and 1x6 pin and doesn't trottle and give bether performance in release 74 than 66.
SP_, all 5.2 maxwells do at least 1500MHz under load. In open case, limiting factor is TDP. Nothing to do with power pins.
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Testing how far I can go with reference 970. You need to give this baby almost +300 to get there (1500). Around 10500 kH/s mining lyra2v2.
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Same settings with quark, hitting TDP and only hashing about 17200 kH/s. TDP mod is all you need if you want to get all out of these.
It has to do with power pins: max TDP depends on how the card is powered. I have two kinds of 970 and the max TDP is higher on the one that has one 8 pin and one 6 pins instead of 2x6.
Furthermore, the power you need to reach a certain frequency varies based on a lot of variables like room temperature, efficiency of cooling, fan speed, the chip itself, etc.
Correlation does not imply causation. I have some cards with less pins that draw more power then ones with more pins. It just happens that in this case sometimes you get cards with more pins that draw more power then cards with less pins. Take some low clocked Gigabyte cards (not Windforce) and compare them to Asus Strix cards...
They can program the bios to draw as much power as they want and it's up to the manufacturer to decide how many aux connectors they want on the board.
It's actually scary thinking some people are using 750tis without aux connectors and sucking it all through the board because they think that wont have any adverse effects. I don't think I'd ever do that or buy 750tis without a aux connector.
thefarm in its ( almost ) entirety are the gigabyte 750ti oc lp ( low profile ) which have NO aux power connectors ...
BUT - they draw their power from the powered usb 3.0 risers as well as from the pcie bus ...
so even though they have no aux power connector - they run really well for a 750ti card ...
there was a time when the whole farm was based on gigabyte 280x oc cards which were ALL run off the ribbon risers - 5 x 280x oc cards per machine ... cable risers melted and burned through their power connection pins - and some destroyed cards like they were firecrackers ...
changing to the usb 3.0 powered risers fixed the majority of power issues - but the gigabyte 7970 oc / 280x oc cards ended dying due to their fan malfunctions ... so not a power issue but a manufacturing / heat dissipation issue on that end ...
#crysx
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