280x Toxic Under-volt

uncle_muddy

Yeah I discovered the button, and made sure that when writing the BIOS it was always lit up, so if anything went wrong I could reboot with the light out. So I have 1 of my 3 back on the standard BIOS at 1.2v for now as I just don’t have time today to muck around any more. But I will get back on it later in the week when I get time.

Ignition75

Ahhh OK, I was doing the opposite, when a card died I would press the button and reboot, it came back every time, then I would unpress, flash VBios and reboot a couple of times and they always came back…

I still don’t quite understand what the button does to be honest…

Pancrisp

Heh, I might need some help undervolting my cards.
Also aiming for that magical 750khash/sec

Ignition75

Happy to help…

Grab your VBIOS from here: http://www.techpowerup.com/vgabios/

Also grab atiwinflash from techpowerup.

Grab a program called VBE7, I think it’s at github.

Instructions for atiwinflash are on the download page and very straight forward.

When you’re changing voltage in VBE7 it’s the one at the bottom of the screen, clock 0, that’s the performance clock, leave the rest alone.

Download the latest VBios from techpowerup.
Flash with atiwinflash.
Grab a bible and reboot.

Most guides say don’t go below 1.1v per card, I can only share my experience:

270x’s - 1.1v is the lowest you can go before you start getting intermittent instability.
280x’s - 1.075v is the lowest you can go with windows, but again, every setup is different.
290’s, no support with VBE7. It’s a bit of a hack, you have to load an Asus VBios onto your 290 or 290x, regardless of what brand your card is, then you can play with voltages in something like Asus GPU Tweak.

With the 290’s though, you can’t hard code it into VBIOS like you can with the 270 and 280’s, so I don’t bother. You gotta do it every time you boot up your OS. It becomes a pain in the @ss so I stopped buying 290’s, plus they are noisy like h3ll and don’t support analogue so Team Viewer runs in commadore 64 mode…

Pancrisp

Hmm, I have the MSI R9 280X
I see a few different versions of the vBIOS, do I just get the most recent one?

uncle_muddy

I just went with the stock BIOS that I downloaded from my card, made the changes to the voltage settings and then pressed the button before uploading the modified BIOS back to my card.

Ignition75

[quote name=“Pancrisp” post=“58063” timestamp=“1391956473”]
Hmm, I have the MSI R9 280X
I see a few different versions of the vBIOS, do I just get the most recent one?
[/quote]

I usually went with the most recent bios version… I found it weird how you would have the same versions released within minutes of each other, or maybe that’s when techpowerup uploaded it…

vex

[quote name=“Ignition75” post=“58010” timestamp=“1391906637”]
Undervolting is awesome.

It took my 4 x Sapphire 280x’s from 1250w at the wall down to 1100w, no loss of speed and each card running 5-10 degrees cooler.

I wasn’t brave enough to go below 1.075v per card, I’ve hard of guys going lower but I was happy with that…
[/quote]

brave enough? there’s nothing to damage, if you undervolt too much the cgminer will crash, you reboot the computer and raise the voltage a bit until you find the lowest stable voltage the card will work on.

i’m running my cards 1.03 to 1.08 (powercolors), 1.125 (sapphire dualx), Gigabyte is the best one with 1065mhz@1.018.

mattmct

Cheers Muddy, this is a great post.

I’ve not had time in weeks to properly play with my rig, so it’s nice to see you have put some great time into it, and I’m glad my thread helped you at some point (in links)

Would you mind sharing your cgminer / sgminer settings? Threads etc also.

I still need to update to the latest BAMT with sgminer and give the multi core passing function a real try. 2 cores for 280x and 1 core for my 2x 7950s.

Morderchai

Man I’m struggling with my Toxic… every .bat file I try it still gives me hardware errors… any guesses where they comming from? I tried almost everything… wich catalyst driver an AMD APP SDK driver? and wich SGminer are you using?

BTW
the cards run up to 800 Hash with this .bat:
-p x -I 13 -w 256 -g 2 --shaders 2048 --thread-concurrency 8192 --gpu-engine 1160 --gpu-memclock 1875
If you can undervolt it and make it run steady you got a solid 800hash per card.

great info on undervolting though!

uncle_muddy

[quote name=“mattmct” post=“58142” timestamp=“1391983463”]
Cheers Muddy, this is a great post.

I’ve not had time in weeks to properly play with my rig, so it’s nice to see you have put some great time into it, and I’m glad my thread helped you at some point (in links)

Would you mind sharing your cgminer / sgminer settings? Threads etc also.

I still need to update to the latest BAMT with sgminer and give the multi core passing function a real try. 2 cores for 280x and 1 core for my 2x 7950s.
[/quote]

No worries mate, I’ll dig my cgminer.conf of later tonight and post it for you

[quote author=Morderchai link=topic=7501.msg58226#msg58226 date=1392053938]
Man I’m struggling with my Toxic… every .bat file I try it still gives me hardware errors… any guesses where they comming from? I tried almost everything… wich catalyst driver an AMD APP SDK driver? and wich SGminer are you using?

BTW
the cards run up to 800 Hash with this .bat:
-p x -I 13 -w 256 -g 2 --shaders 2048 --thread-concurrency 8192 --gpu-engine 1160 --gpu-memclock 1875
If you can undervolt it and make it run steady you got a solid 800hash per card.

great info on undervolting though!
[/quote]
I started to get hardware errors if you aim too high! Try adding this and see what you get “–gpu-powertune 20” also I’m running under BAMT which may make a difference, I would that when I use windows with the same settings on higher hash rates, I start to get issues. Going to need a bit more information about your setup to help you sort it out, Mem CPU, PSU ect…

I’ve caused myself another problem by undervolting now… I used to use the rig to heat the office whilst I was sat in it all day working, now it’s undervolted I have to turn the heating back on ::)

UM

Ignition75

[quote name=“uncle_muddy” post=“58229” timestamp=“1392055904”]
[quote author=mattmct link=topic=7501.msg58142#msg58142 date=1391983463]
Cheers Muddy, this is a great post.