Does underclocking reduce power consumption? - page 2.

CYPER

hero member

Activity: 812

Merit: 502

Quote from: Yannick on July 10, 2011, 09:14:00 PM

Or should I buy this?
http://www.arctic.ac/en/p/cooling/vga/20/accelero-xtreme-5870.html?c=2182
I'm using the sapphire 5870 now, I really don't like the noise if their fans blow over 50%. Sad

Or is it ok as long as I keep my temps below 90°? My target was 80° but I read that below 90° shouldn't be a problem for the 5870's.

I wouldn't recommend you keep your cards at constant 90°, not even 85°. Try to be below 80°.

Yannick

member

Activity: 68

Merit: 10

Or should I buy this?
http://www.arctic.ac/en/p/cooling/vga/20/accelero-xtreme-5870.html?c=2182
I'm using the sapphire 5870 now, I really don't like the noise if their fans blow over 50%. Sad

Or is it ok as long as I keep my temps below 90°? My target was 80° but I read that below 90° shouldn't be a problem for the 5870's.

KKAtan

newbie

Activity: 50

Merit: 0

As rethaw noted, educing Voltage makes power consumption go down very significantly. You should of course note that reducing voltage often needs reduction in clock speed as well, they accompany each other.

Other things that can help lower power reduction:

If you use this client: http://forum.bitcoin.org/index.php?topic=3878.0
You can tweak the -s flag

Quote

Q: My temperatures are too high, can I throttle the GPU so it runs slower but cooler?
A: If you are mining using OpenCL you can use the -s flag a value such as 0.01 in order to force the GPU to sleep for 0.01 seconds in between runs. Increase or decrease this value until you have the desired GPU utilization.

And of course the -f flag.
Using -f60 or -f120 can also significantly reduce consumption.

CYPER

hero member

Activity: 812

Merit: 502

Yes, I got mine @ 300Mhz, but have no data for the power consumption decrease. Probably not much to have a profound effect on the power bill.

rethaw

sr. member

Activity: 378

Merit: 255

I believe it is also possible to reduce the voltage to the memory using RBE for some cards. I would be interested to hear other's experience with this, I believe this would more significantly reduce consumption than reducing clock alone.

Pentium100

full member

Activity: 126

Merit: 100

Just get used to sleeping with the fans at full speed. Do it like this: every evening, increase the fan speed by 1% or so from the previous night, and soon you won't notice that the fan is running at full speed.

CYPER

hero member

Activity: 812

Merit: 502

Power consumption is less, but not a significant difference.

Yannick

member

Activity: 68

Merit: 10

Hey you guys,

At night, I'm underclocking my hardware to try and catch some sleep while the fans are more silent.

So I underclock both 5870 cards to core 700 and mem 250. I notice that the gpu fans are only spinning around 50% and I'm generating ~600 Mhash/sec.

However, GPU1 and GPU2 usage is still the same: 98% !

During daytime, I obviously overclock the cards with max fan speed and get ~840 Mhash/sec.

Now I'm wondering: the fact that GPU usage is still 98% while underclocked at night, does this mean that power consumption is still the same as if they were overclocked?

Thanks!

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