Boosting hashcat performance with YouTube

[illyria]

Inspired by epixoip's tweet earlier today, I decided to spend a few minutes documenting my own similar experience.

I never previously reported this,  as A) I found a work around, B) the problem was very sporadic and C) never saw anyone else with similar reports, and figured something in my setup was wonky.

System setup:
Windows 10
CPU: A8 5500
RAM: 16GB
GPU: GTX1070
Hashcat: 3.0.0 through 3.5.0
Nvidia drivers: 368.xx through 381.xx

The original discussion referenced in the tweet mentions Minecraft as the instigator, but my experiences has it working with both YouTube and MPC-HC, ie. anything that offloads work to the GPU

First let's look at MSI Afterburner monitor outputs:




A] Starting up hashcat

Code:

-m 0 -a 0 -w 3 ?b?b?b?b?b?b?b

letting the GPU warm up


B] GPU has reached temp limit, and is hashing away at 13.3 GH/s



C] Opening browser and navigating to https://youtu.be
Presto! Speed jumped to 14.6 GH/s

Notice how GPU usage stabilises at close to 100% and power consumption is less flaky
NB! No need to playback any videos or even load a specific video, just loading the front page will do the trick. Same with MPC-HC just load the video and pause it.



D] Closing browser, and everything returns to "normal".

As I mentioned in the beginning this behaviour is very sporadic. After a reboot, I may see normal behaviour and have GPU utilisation at 100%, only to see it 3 hours into a hash-cracking run switch to the more irratic behaviour documented above.

And for those wondering why Power usage sits at 50%, I will refer you to hashcat's tweet and accompanying Google Docs spreadsheet on performance vs power consumption.

50% power limit: 14,600 MH/s @84W = 173 MH/s/W
100% power limit: 17,300 MH/s @148W = 117 MH/s/W

For the record, similar behaviour is exhibited with the power limit set to 100%.

[kiara]

so weird
have u try to OC and use these methods to see if u are able to crank the gpu alil bit more?

[illyria]

I have not, per say. The trick I use with loading youtu.be et.al. is really to regain lost performance, due to whatever causes the issue.

[kiara]

did u maybe try to use both?
youtube and MPC-HC to see if u get more speed when both are open?

[alex#23]

I got this once years ago. It was possible to increase download speed by causing a high load. In the end i figured out, that i am not increasing my download speed but reducing my "clockspeed" which let it look like a faster download

[illyria]

did u maybe try to use both?
youtube and MPC-HC to see if u get more speed when both are open?

No, I do not expect GPU utilisation to go above 100%

[epixoip]

This is all surely related to power management, power states, and clock rate. I would say your GPU is not properly tuned, but I'm honestly not sure how to properly tune a GPU within Windows. It looks like you have Afterburner, is there nothing you can do with it to set PerfLevelSrc, Clock Offset, etc?

[illyria]

This is all surely related to power management, power states, and clock rate. I would say your GPU is not properly tuned, but I'm honestly not sure how to properly tune a GPU within Windows. It looks like you have Afterburner, is there nothing you can do with it to set PerfLevelSrc, Clock Offset, etc?

If the lax performance was constant I would agree. But as mentioned sometimes it happens after hashing away for a few hours, sometimes it runs perfectly.

As you may have noticed, I disabled temp-management in hashcat. Sometimes it works great, other times it feels that there's no need to speed the fan up until temp limit has been reached, and then it runs full speed until temp drops 1 degree below limit, and then it idles the fan again. So whether it's the card itself that is a little wonky, or maybe it just doesn't play well with my 5 year old AMD Mobo/APU combo.

Either way, I'll have a look into tweaking settings, and see if anything can be gained from there.