Topic: Undervolting a 5870 and a 5770 to achieve better MH/J performance (Read 15510 times)

I did a pencil mod and thanks God, it did not go south!

After checking the datasheet, I decided to play with the voltage divider. The chip is programmable; but thanks to the laziness of Gigabyte engineers, they did not implement that feature.

Instead, a hard-wired voltage divider is used and that voltage divider will serve as reference voltage

http://desmond.imageshack.us/Himg28/scaled.php?server=28&filename=84097862.png&res=medium

I used a pencil and get the 5k Ohm resister went to 4.5k.

Voltage measured at the chokes changed from 1150 mV to 950 mV. Beyond my expectation

Dont blame me if it goes south:
http://www.overclock.net/t/997130/where-is-5750-powercolor-vtx-red-pcb-pencil-mod#post13226546

My cards use a god damn uP6204BJ

I am looking for a way to hard-mod them. Maybe a reverse of pencil mod?

It's kinda strange, the MSI Hawk 5770 also uses that VRM chip. And MSI told that the Hawk series is very advanced and controllable

Some lower end cards are not controllable.  The VRM regulator can't be altered by drivers, bios, or anything else (expect maybe some hardware mod).  The controller has a static value and the model chosen at construction time determines voltage. 

I know it is hindsight 20/20 and all that but generally this is why I stick w/ "upper half" cards (say 5850 or higher in 5000 series) and AMD reference designs.

Damn it! I also have some 5770s which doesn't have programmable voltage controller.

I flashed BIOS with many different voltages, it showed new values nicely but the card just ignore BIOS and consume same amount of energy.

WTF

^ Woops!

Here's the correct second link (about putting a Sapphire BIOS on the card):
http://forums.bit-tech.net/showthread.php?t=185918

Be careful though! Card-bricking is a possible outcome.

You linked to the same thread twice.

Hmm.  Worth trying.  If it works I will give you a couple coins.  I already removed waterblock and my replacement thermal pads arrive today so I will remount the original heat sink, and try to flash it.  Honestly if I killed it w/ a bad flash I wouldn't be too sad. 

If it works reliably again well that is a nice score.  I will let you know.

Would your XFX happen to have the rev. 1 BIOS? I've head that this BIOS from XFX is bad, and that - in general - XFX BIOSes are worse than other BIOSes. Take a look here:
http://forums.guru3d.com/showthread.php?t=329453

Unless you're done with trying to fix this card, putting a Sapphire BIOS on it might help. Here's a guide on how to do that:
http://forums.guru3d.com/showthread.php?t=329453

Without being a video card expert, I'm pretty sure that all the symptoms you describe *could* be caused by a poor BIOS.

Lots of things.  BAMT never sees the BE although it sees every 5970 just fine.  aticonfig -intial -f doesn't solve it.  If I add it to an existing windows machine it never sees the card.  It shows up in device manager but even catalyst control center (as well as GPU-Z, cgminer) never sees it.  The only thing that works is a clean install.  Installing drivers 12.1 causes BSOD but just with this card.  Remove the BE card and it installs just fine.  Insert BE and it BSOD on boot up.  Remove it and it works fine again.

It shows up in the "wrong order" in cgminer.  It makes the config file out of order relative to the display.   Every other card has the pair of GPU in the same order but the BE seems to put them randomly (it doesn't change but the order is random on each clean install).   Sometimes on a clean install it will show up as "disabled" in CCC.  It takes 2 reboots and it magically will show up again.  It doesn't like running at >835 Mhz even when watercooled w/ 50C core temps.  I can't change the voltage using cgminer (although I can w/ every other 5970 I own).  In cgminer it routinely stops showing temp or fanspeed (which is 0% because of watercooling).

Need I go on.  It is a piece of shit.  Maybe it was a lemon but weird when actually mining it mines just fine.  I have removed the waterblock from it and waiting on some TIM to put the stock heatsink back on.  If I can get it stable enough for gaming it likely is being ebayed. Honestly I have spent more time on this piece of shit then the other 14 graphics cards combined.  I should have given up a long time ago but I am stubborn.  Maybe i got a lemon but I am not taking any chances.

How does this "weirdness" manifest, exactly? Would be nice to know since I'm currently looking for a 5970 to purchase.

Yeah physically it is but it seems to be an oddball when it comes to drivers and the like.  I don't know what they did to it but it doesn't like to play nice with other ATI reference cards.  I likely will ebay it and grab another ATI reference.  It has been (at least for me) a complete and utter pain in the ass.

Isn't the XFX Black Edition 5970 a reference card? I know the XFX 5970 Black Edition Limited isn't a reference card, but the non-Limited version sure looks like all the others (except for some stickers).

I have an xfx BE which I wish I never bought.  I would trade it for a reference ATI anyday.  Hell I would throw in $100.  Grr.  I don't have those problems but it is just "weird" when it comes to drivers.

Anyways.  You may want to check xfx website or google around.  xfx has a custom voltage mod tool maybe that will work.  I have a feeling xfx did "something" to the cards.  I am tempted to flash the bios to the "basic" XFX 5970 but am afraid I will kill it.  I will never buy a BE again.  AMD reference is good enough for me.

I have a couple 5970's (black edition) that I can't change the voltage on. I also have not been able to change the fans speeds either. Kind of strange, I have several of the cards and just two of them do this. Despite what pc there in. I had to put a fan controller on them and cut the blue fan wire to gain control of the fans speeds.

I found one:
http://www.newegg.com/Product/Product.aspx?Item=N82E16814125316

I have a couple of those, and I can't change the voltage no matter what.

I have not seen any 5970, 5870s, 6990, or 6970 without adjustable VRMs.  I would imagine the same applies to 7970 & 7990s too.

It is generally the mid range and low end cards.  The reason for removing them has more to do w/ support calls & RMAs.  There isn't a lot of profit in midrange cards and most of that market is casual gamers.

Does anyone know if there are any 'cheap' 5970s out there that don't allow undervolting, and if so, which brands/models? I'm considering buying a 5970 but I don't want to risk getting one that doesn't undervolt (if any exist at all).

Shows what I know. I thought adjustable VRMs were so cheap that no one would bother not putting one on the card. But then again I guess dynamically adjusting the voltage is a bit more complex than simply buying a capable VRM and slapping it on the card (like the additional software/BIOS development required).

Bingo! That's my problem. I can "change" the voltage, the software even indicates me the new voltage. But in reality, with a Kill-a-watt plugged in it, you see no difference. I can even input 0V, the software takes it, and the card run as normal.

I believe it could be possible to limit the voltage through the BIOS, but I'm don't know how yet.