• From: portland, oregon, usa
  • Registered: 2008-02-13
  • Posts: 22

Topic: FF400 on bus power + MBP + active charging of battery = CPU runaway??

hi. i am swimming in CPU overload..

i have a 2011 quad core MBP, os 10.6.7, ableton 8, rme ff400 (v2.90)..

this has been ROCK SOLID for me, since i got the machine over two years ago.

last week, on a trip, (for a gig.. argh!!) i suddenly came up against a WALL of CPU usage in ableton live, jumping from the average of ~40 percent usage i get from most of my DSP intensive sets, to 50, 60, 70, 80 ,90.. 120!! percent CPU usage, as measured by ableton ( i think it measures 1 core at a time?? ) this of course results in total signal degradation, stuttering, etc..

so.. after a round of troubleshooting, including SMC reset, trying different power adaptors, replacing the FW cable, using time machine to restore back to known-good install, i have arrived at a couple of scenarios where i can reliably re-create this occurence..

1 - MBP on battery power, ableton running, FF400 connected, set to bus power.. system runs well enough UNTIL i connect the 85w adapter to CHARGE THE BATTERY, 1-3 minutes later, during ACTIVE CHARGING ONLY (not 'battery is full' trickle charge) my system will be effectively useless.

1 - MBP adaptor connected, battery charging actively, live running, FF400 on _AC POWER_.. if i switch the FF400 to BUS POWER.. same thing happens.. in fact i can get it to fluctuate up and down by switching back and forth between BUS and AC power..

so, AFAIK, the two common factors here are the FF400 drawing power from the MBP, and the MBP battery being ACTIVELY charged (orange light, not  at the end of charging cycle ) . i managed to play the gig i travelled for by fully charging the battery and running the system on combined AC and battery (green light, 'battery is charged', etc..)

any ideas?? bad battery maybe?? something happen to my FF400 causing it to draw more power than it should?? i don't know why this would affect CPU usage, other than perhaps a looping competition for system resources ? the fans are definately spinning up during this process..

any help would be appreciated!! it's not an easy thing to bring into the apple store and get them to replicate, w/o leaving them my fireface hmm

soundcloud.com/wndfrm

2 Reply by MC

  • MC
  • MC
  • Administrator
  • Offline
  • From: Germany/Thailand
  • Registered: 2007-04-06
  • Posts: 24,913

Re: FF400 on bus power + MBP + active charging of battery = CPU runaway??

Please search the forum, this effect has been reported before.

Regards
Matthias Carstens
RME

MC's Website

  • From: portland, oregon, usa
  • Registered: 2008-02-13
  • Posts: 22

Re: FF400 on bus power + MBP + active charging of battery = CPU runaway??

ah, i can't seem to find anything similar, would you mind pointing me in the right direction??? it's not a drop-out issue.. sorry, i am just really frustrated right now.

soundcloud.com/wndfrm

4 Reply by MC

  • MC
  • MC
  • Administrator
  • Offline
  • From: Germany/Thailand
  • Registered: 2007-04-06
  • Posts: 24,913

Re: FF400 on bus power + MBP + active charging of battery = CPU runaway??

http://www.rme-audio.de/forum/viewtopic.php?id=16935

Regards
Matthias Carstens
RME

MC's Website

  • From: portland, oregon, usa
  • Registered: 2008-02-13
  • Posts: 22

Re: FF400 on bus power + MBP + active charging of battery = CPU runaway??

MC wrote:

http://www.rme-audio.de/forum/viewtopic.php?id=16935

ok, that seems similar, however several factors are different.. possibly linked by a heat issue? i have not been measuring this, bt the fan does spin up, however my fans run frequently regardless, and have done so for quite some time.

i am not running lion or snow lion, still on snow leopard... this seems to rule out power management issues with os 10.7+ and live.

kernel task is also not always eating up resources, i noticed it once, but it doesn't do it everytime. battery percentage seem to have little to do with it, aside from the difference between active charging and being considered 'charged'.

any further insights?

thanks.

soundcloud.com/wndfrm
  • Registered: 2008-01-01
  • Posts: 3,025

Re: FF400 on bus power + MBP + active charging of battery = CPU runaway??

I can check this again on my MBP 2011 17" with OS X 10.6. But since the last incarnation of OS X Leopard was 10.6.8, you maybe should update first?!

Generally Firewire based CPU load problems with several different audio interfaces where reported with Leopard on Gearslutz some years ago. I did not experience those myself, though.

  • From: portland, oregon, usa
  • Registered: 2008-02-13
  • Posts: 22

Re: FF400 on bus power + MBP + active charging of battery = CPU runaway??

i tried 10.6.8 once, it broke most everything, so i went back to 10.6.7.. i've been using the current setup for about 2 years, with extreme reliability.

the strange bit is the change is so sudden.. this leads me to think of a hardware issue, perhaps something became unseated during flight, or travel..   i think i will just have to take my MBP in for examination, perhaps get it cleaned out (dust, etc..) .. i am somewhat stymied at this juncture.

thanks for the input.

soundcloud.com/wndfrm