Miners all slowing down when no monitor is connected

[transposon]

Hi Guys,

I am a new miner and am trying to figure out what is going on here.  With all of my 280x s, they average 15-20KHs slower when they don't have a monitor connected to at least one card on the motherboard.

As soon as I connect a monitor to anyone of the cards connected to the motherboard all the cards start hashing faster.

I am running 2 x 280x s per motherboard and using the Beta 9.5 AMD driver with CGMiner 3.5.1

Any ideas?

Thanks.

[sibilant_doge]

I had the same problems with my laptops. When the screen would go off, my has rate would drop or fall off completely even with settings to not go to sleep. I just ended up having to do the longterm monitor burn.

[infinitybo]

Hi Transposon that would be preferable to ask your question by using the "Mining" section and btw, welcome aboard !

[Flashman]

That's odd that that problem has returned with newer cards, it used to be a problem a year or so back with older catalyst drivers, but then it was fixed in the driver end, and we've not had to worry about it...

But the fix then was to use monitor "dummy plugs" basically these were a DVI to VGA adapter with some resistors stuffed in across the outputs such that it thought there was an analog monitor connected. These are rather simple to make or can be ordered online from some of the crypto mining hardware specialists. (I'm thinking memory dealers and winnipeg technology and computer renewal at the moment) But there was some suppliers in the classified here, but they may have stopped offering them recently due to lack of need... although if the newer cards are going to be a bugger again, I suspect they will be very willing to sell them again.

Here's one page on how to make one...

http://www.geeks3d.com/20091230/vga-hack-how-to-make-a-vga-dummy-plug/

[transposon]

This is a pain.  The difference between monitor and no monitor seems to be getting larger.  THe averages while no monitor is plugged in are about 80kh/s lower now per card.

[tarod]

yep dummy plugs are the way to go. Trick that card into thinking its plugged in

[coinspoolco]

It is slowing down because of the power management of the driver. ADL device is getting disabled and only OpenCL will be active, because there is no display. Just get a dummy plug it will help, or switch to linux.

[infinitybo]

@Coinspoolco  Sometimes that's true because the stuff is not getting enough power.