Fun with GPU's

[Dirk Broer]

For whoever wanted a real heavy GPGPU credit gobbler:

Looks like they're gobbling Watts (=Dollars or whatever you use paying your power bill) as well...
That ARES II will earn you a place in the hall of fame of your energy supplier!

[Terry1953]

OK Guys here's the problem: I have several machines running dual GPU's but, with Catalyst, I can only control the main GPU as to overclocking and fan speed. Is there another way to control the second card?

#1_6970.gif #2_6970.gif

[Dirk Broer]

I see from your pics they're not Crossfired, enable it and try again to change the settings of the 2nd card.
You can disable it afterwards or try and see whether BOINC is affected by the Crossfire. My bet is that BOINC does not see the Crossfire, but just two GPUs.

[Terry1953]

I tried that and as soon as I pull the bridge off it marks the 2nd GPU to disabled (it still runs a wu) and resets it to default settings. It's not really a huge problem I just like to OC everything 20 to 30%.

[Jason1478963]

I have used extend the desktop with a dummy plug that semms to work well for me. This has let me see the second card in AMD catalyst. It might be worth a try to look at MSI afterburner to see if it would see the second card without the extra work of a dummy plug or second monitor.

[Dirk Broer]

When you enable crossfire you need that bridge on your GPUs.
Bummer that it doesn't keep it's settings once disabled.

[NerdLifeAMD]

hey guys i have a crossfire question // do i have to use crossfire with two card or can i use them the old school way as separate cards? since i wont be playing games on the crunch bots anyway it seems like i can avoid some issues by not using crossfire since unless im mistaken there would be no benefit to work units by enabling it?

[Dirk Broer]

You don't have to use crossfire, and BOINC-wise there's indeed no benefit.

What you do have to do is add -using a very basic editor- the line between 'options' below to your cc_config.xml file -and you have to make a cc_config.xml file using a very basic editor like notepad (in Windows) when you can't find such a file in the directory where the BOINC Data is stored (so not in the BOINC directory itself). In Win7 that would be in C:\Programdata\BOINC\

<cc_config>
<options>
<use_all_gpus>1</use_all_gpus>
</options>
</cc_config>

Default directories for BoincData
Windows 98/SE/ME: C:\\Windows\\All Users\\BOINC\\ or C:\\Windows\\Profiles\\All Users\\BOINC\\
Windows 2000/XP: C:\\Documents and Settings\\All Users\\Application Data\\BOINC\\
Windows Vista/Windows 7: C:\\ProgramData\\BOINC\\
Linux: wherever you unpack it/BOINC/
Macintosh OS X: /Library/Applications Support/BOINC/

[NerdLifeAMD]

My son Ryan and I found out today that Crossfireing 2 6870's with only a 750 watt power supply is a bad idea. It was up and running like a house on fire until I noticed that the temps on the gpu's were 61c and 84c I shut windows down and asked Ryan to pull the power cable out of the back of the machine so I could pull the hot gpu and I was going to clean it and put some arctic silver 5 on the cpu. When he grabbed the power cable running from the wall socket to the power supply it was so hot it left a mark on his hand! The second gpu wasn't pulling the power it needed and was in the process of frying the whole setup. So we're just going to scatter them over various machines and not order any more. They sure do suck the power.

The power cord from the powers supply to the wall being hot is a sign that you need a better power cord.
make sure you don't have a knock off cord mixed in yous stuff. I had the same issue when i mistakenly used a cheap cord with
a lower gauge copper in the jacket to plug in my blade and its only 400 watts. it looked the same on the outside but when
i cut it in half which is what i do with defective cords of any type so they don't make it back into circulation.
I found it was mostly rubber with very little wire inside. there is absolutely no reason for a single computer to make an ac cord hot.
for example i have a 100 foot cord plugged into 3 power splitters. I had 2 servers 3 p4s 3 routers and a window unit AC unit
plugged into it as well as a crt display plugged into it ( thats easly well over 2000 watts )and it only got warm where the wire was bent right before the wall socket