hashcat Forum

Hey everyone,

I recently installed hashcat due to a CTF I participated in and it is an amazing tool with some great documentation. However I am a little confused because when I run hashcat and I look at windows task manager it has it running with a much higher CPU percent than GPU.

C:\Users\Jordan\hashcat>hashcat -I

hashcat (v5.1.0) starting...

OpenCL Info:

Platform ID #1
  Vendor  : NVIDIA Corporation
  Name    : NVIDIA CUDA
  Version : OpenCL 1.2 CUDA 10.1.95

  Device ID #1
    Type           : GPU
    Vendor ID      : 32
    Vendor         : NVIDIA Corporation
    Name           : GeForce GTX 1070
    Version        : OpenCL 1.2 CUDA
    Processor(s)   : 15
    Clock          : 1797
    Memory         : 2048/8192 MB allocatable
    OpenCL Version : OpenCL C 1.2
    Driver Version : 418.81

C:\Users\Jordan\hashcat>hashcat --benchmark
hashcat (v5.1.0) starting in benchmark mode...

Benchmarking uses hand-optimized kernel code by default.
You can use it in your cracking session by setting the -O option.
Note: Using optimized kernel code limits the maximum supported password length.
To disable the optimized kernel code in benchmark mode, use the -w option.

* Device #1: WARNING! Kernel exec timeout is not disabled.
             This may cause "CL_OUT_OF_RESOURCES" or related errors.
             To disable the timeout, see: https://hashcat.net/q/timeoutpatch
OpenCL Platform #1: NVIDIA Corporation
======================================
* Device #1: GeForce GTX 1070, 2048/8192 MB allocatable, 15MCU

Benchmark relevant options:
===========================
* --optimized-kernel-enable

Hashmode: 0 - MD5

The high CPU use on startup is because of the kernel compilation. This is done by the opencl runtime which is provided from the opencl device driver. It creates some initial CPU load only for a short time on startup but disappears after a few seconds. Note that in benchmark mode, there's almost all the time initial startup, therefore you will have the CPU busy all the time compiling GPU kernels.

(02-13-2019, 07:06 PM)atom Wrote: [ -> ]The high CPU use on startup is because of the kernel compilation. This is done by the opencl runtime which is provided from the opencl device driver. It creates some initial CPU load only for a short time on startup but disappears after a few seconds. Note that in benchmark mode, there's almost all the time initial startup, therefore you will have the CPU busy all the time compiling GPU kernels.

Oh that makes sense! I do have another question if you can help with it.