100% CPU with 2 cards

[RoadStress]

What is causing the CPU to stay at 100% when mining with 2 cards? (second has dummy plug) Drivers or OpenCL? What drivers or OpenCL to use to avoid the CPU bug? Thank you.

[1714952579]

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[1714952579]

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[1714952579]

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[Bitcoin_Silver_Supply]

There is no known cure in Win7 with two cards as of yet. Supposedly even some Linux users are experiencing this. The best you can do is set your cpu affinity to one core so that your other cores remain free.

[bmgjet]

Problem just started with me when I added my second card, Setting affinity to only 1 cpu helps if you have a multi-core cpu so then its atleast limited.

Also I fired up a CPU miner on that same core, Doesnt slow down the gfx cards at all and atleast the 99% useage is getting sent somewhere productive.

[haydent]

yeah i have to underclock cpu to keep my fan noise and heat down.

[haydent]

Also I fired up a CPU miner on that same core, Doesnt slow down the gfx cards at all and atleast the 99% useage is getting sent somewhere productive.

i just tried it for fun, but it reduces my gpu speeds to cpu speeds (under .5Mhs) so i would have to use a core not being affinity by the gpus. not worth it, would be more effectiev for me to oc my gpus a bit more.

[nafai]

Weird, I'm on Win7 with two cards and have never experienced the 100% cpu problem. I mine pretty much 24/7 (of course) and my cpu is always around 30-70% on all cores.

[haydent]

Weird, I'm on Win7 with two cards and have never experienced the 100% cpu problem. I mine pretty much 24/7 (of course) and my cpu is always around 30-70% on all cores.

you have it too. you get 100% when you set an affinity to one core, rather than it being spread out. it seems to produce less heat this way and is more responsive.

[bmgjet]

What miner are you running,
Im running CGMiner.
With 1 card it was only using 0-1% cpu
2 cards running from same process it uses 99% or if set to cpu0 49%
2 cards running from 2 processes it uses 15-20% per process set to cpu0 so total 40%
2 cards running from 2 processes and a 3rd process for the cpu miner and them all set to cpu0 back to 49% but I get an extra 0.8mhash from the cpu with no slow down to the gpu and no extra heat or power usage at the wall.

[nafai]

Ah.  Well I never have a responsiveness problem, I can play portal 2 or world of warcraft or whatnot just fine while mining full speed and overclocked. But I will definitely have to try setting the affinity to see if it affects my temps.

My CPU cores were running about like this when I was only using one card though, IIRC. Maybe a little lower but I definitely noticed the CPU usage even on one card.

I'm using guiminer to fire up 2 phoenix miners, one for each card.

[haydent]

i have started a thread at amd dev forum - opencl section about the 100% cpu usage bug with >1 gpu installed. feel free to jump over there and post your support for this issue being addressed...

http://forums.amd.com/devforum/messageview.cfm?catid=390&threadid=153211&enterthread=y