07-18-2014, 10:13 AM
from what i can tell in that video and a couple other videos i watched of people tearing down the same model, those fans don't plug into the GPUs, they plug into the mainboard. so they appear to be system fans that the GPUs tap into via a heat pipe.
it's entirely possible that the GPU driver does not know about those fans, or cannot control those fans, or can only control one of the fans, or can only see some common controller on one GPUs that actually controls both fans simultaneously. laptops are a bit complicated in that the oems pretty much have free reign over the design, and do all sorts of things that the chipset manufacturers may not have accounted for, so nothing is really out of the realm of possibility here. you would need to really dig into the low-level specifics of your laptop to find out what's going on.
the important thing to note here though is that hashcat doesn't actually control your fan speed, that is purely there for reference. you need to use some other utility to actually control the fan speed.
another important takeaway is that the cooling solutions in laptops are absolutely not made to cope with the electrical draw and heat generated by compute workloads. running hashcat on a laptop for any extended period of time is a sure-fire way to ensure the untimely death of your system.
it's entirely possible that the GPU driver does not know about those fans, or cannot control those fans, or can only control one of the fans, or can only see some common controller on one GPUs that actually controls both fans simultaneously. laptops are a bit complicated in that the oems pretty much have free reign over the design, and do all sorts of things that the chipset manufacturers may not have accounted for, so nothing is really out of the realm of possibility here. you would need to really dig into the low-level specifics of your laptop to find out what's going on.
the important thing to note here though is that hashcat doesn't actually control your fan speed, that is purely there for reference. you need to use some other utility to actually control the fan speed.
another important takeaway is that the cooling solutions in laptops are absolutely not made to cope with the electrical draw and heat generated by compute workloads. running hashcat on a laptop for any extended period of time is a sure-fire way to ensure the untimely death of your system.