Friday, August 28, 2015

No sense in wasting the heat and air movement

My 6x GTX 970 open-air password-cracking rig.



  • Case: Custom Spotswood
  • - Case cover: Not pictured. Mostly for transport purposes, usually runs with the cover off
  • - Handle: For carrying. Sorta helpful, but a little unwieldy
  • Board: GA-990FXA-UD3 rev 4.0. Leave IOMMU enabled; add "iommu=soft" to grub parameters (otherwise, USB and NIC won't work)
  • - Sound: No onboard sound - mini onboard speaker ($4)
  • CPU: AMD FX-8350
  • Memory: 32G for PRINCE headroom
  • OS: Ubuntu Server 14.04 LTS 64-bit
  • PSUs: 2x Corsair RM1000. No fan movement unless loaded. Room for growth if cards get upgraded
  • - Dual PSU adapter: Vantacor
  • - Power switch: Had to get a power/reset switch/cable - none onboard
  • GPUs: 6x EVGA 04G-P4-2974-KR. Max 165W per card
  • - Risers: Non-USB (ribbon) risers. The four x16 slots have powered x16-to-x16 ribbon risers, which isn't necessary for most GPU-centric cracking. x4 or higher is better for John the Ripper, but x1 is fine for cudaHashcat. The two x1 slots have unpowered x1-to-x16 ribbon risers. The USB-based risers would *not* work with this board. The symptom was that only a couple of the cards would work at a time.
  • - GPU fans: locked at 50%. Temperatures do not break 78 at normal house temps, and do not break 72 in cooler rooms

Power consumption:

  • Idle: 105W
  • Idle, with GPU fans forced to 50%: 120W
  • Full CPU load (all 8 cores, OEM CPU fan at 3600 RPM): 265W
  • No CPU, oclhashcat job loaded but paused: 310W
  • Full GPU-only oclhashcat job in progress, minimal CPU: 1050W
  • Full processing load (CPU and GPU): TBD

UPDATES - Performance:

UPDATE - upgrades over time:

  • GPUs are now 6x 1080s
  • Ubuntu 18.04 LTS
  • CUDA 10.1 (upcoming hashcat 6.0 restores CUDA support; now you can use all of your GPU memory! - good howto from Puget Systems here)
  • almost always latest hashcat from GitHub
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