Only two very big capacitors at the input stage (220v) are dangerous.

Good news is the capacitors do not hold much charge; you can short-circuit them with a screw-driver. There will be some small sparks, but not much. Of course do not hold the metal part of the screw-driver, or you will be screwed.

These capacitors are nothing compare to audio capacitors (10000 uF+); they can explode like mini grenades

Correct!

No, I'd rather not to place any expensive stuff outside of my house

And I really hate those nasty bugs, they love the blinking leds

Seriously?

It is really strange to hear you say Linux is not stable. lol

Check the thread about shorting two pci-e pins, some motherboards require it

I had too many problems with my 6950 and Windows, in the end I installed Ubuntu and flashed the card with new clock settings and voltage levels

Now my headless machines run on a usb flash drive and require no attention from me; even when in case of power outage, when the power comes back they automatically boot themselves and start mining

If any of you have a kill-a-watt and some spare time, please help doing test:

-With cgminer, set target temp 65oC, auto fan , record the wattage (average for 1-2 minutes)

-Repeat with target temp 75oC

We all know that the high temperature, the higher current leakage in the transistors. But the question is how much higher?

Suppose same GPU with constant clock, fan, workload...; at 80oC it consumes more energy than when it is at 70oC. It is because of current leakage at higher temp is much higher, VRM efficiency decrease with VRM temp

There is a interesting article here:

http://www.techpowerup.com/reviews/Zotac/GeForce_GTX_480_Amp_Edition/27.html

"so for every °C that the card runs hotter it needs 1.2W more power to handle the exact same load."


Have you ever measure your card to see how much additional power does it take when the temp increase 1oC?

This machine I also need to use it for something else, not a dedicated miner.

I am using a minimal version of Ubuntu Natty; without xdm,gdm or gnome. I installed xfce4 and startx directly from rc.local

The script was running fine if I run it from terminal; but not from cron

What kind of env does cgminer need?

I set DISPLAY already (although not needed if I don't want monitoring functions); execute cgminer from full path. What else?

Could you guys help me with cron and cgminer? I need a sample script that can use to start cgminer from cron

I tried many different methods but could not make it; cgminer just did not run and did not create any log output

The same script was used to start phoenix without any problem! What a headache for me

OK, Maybe I need to disassemble one dead fan to get more info

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



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

Btw I also want to said that I drill from the bottom, not top. It is quite strange for me to see you remove to top sticker which has "Sapphire" word


If you check the previous pic, you will see that they drilled the bottom, non-moving part of the fan.

I re-oiled several fans already.

I'd suggest that you could use a normal knife, small one, with good tip. Then drill a hole right in the center of the fan,  you will see the metal shaft after several tries.

Don't use high performance electric drill

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

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

I have a quite strange 5770. When it runs it creates some a repeated grzzz/squealing sound.

-It is not the fan. I hold the fan still for a brief moment the sound still there
-It is not the temperature, 50 or 60o the sound was still the same.
-It CHANGES together with the core clock! If the clock is 150Mhz, I still can hear the sound but the interval is longer. At 900Mhz the sound frequency increase rapidly. But it is just the frequency of the sound changes; loudness is still the same.

Do you have any idea what is that sound? How to fix it?

No.

Do yourself a favor and stop think about it.

No problem, i'm using a dirt cheap celeron 331 (underclocked and undervolted)

Damn it still draws a lot of power; but i've no other choice since my motherboard can't run a 420, and a 420 is quite expensive compared with a 331

I have a question that would like for your comments

With GPU-Z we can get GPU's temperature information from 2nd and 3rd sensor; to my observation the 2nd and 3rd sensor always indicates around 5-7 degree hotter than the 1st sensor.

With Linux, how can we do that? I mean getting the additional information the 2nd and 3rd sensor

And the sensor which is reported by "aticonfig --odgt" is also the first sensor listed in GPU-Z? Or it is the 2nd or 3rd? Googled for several hours but I could not find anything useful.