What's the deal with gfx cards with 2-pin fans?

[sheh]

I noticed that some mid-tier cards, like some GTX 650 models, come with only a 2-pin fan. I assume that means no speed monitoring and no speed control (unless there are cards that support voltage-based speed control?).

Considering these aren't super low-end cards, and the manufacturer savings are probably less than a dollar, don't you find that a case of poor judgment?

 

[Deders]

I expect it's voltage controlled, can't imagine them running full tilt all the time.

 

[ViRGE]

Bingo. They use voltage to control the fan speed, which works to an extent but there's a minimum voltage (and thus speed) that's required.

 

[sheh]

Which cards did you have that controlled this way? Did you find it limiting in practice?

What about RPM monitoring?

 

[ViRGE]

Which cards did you have that controlled this way? Did you find it limiting in practice?

What about RPM monitoring?

2 pin: Voltage control, no monitoring
3 pin: Voltage control, RPM monitoring
4 pin: PWM control, RPM monitoring

2 pin fans are far from ideal, but they are very common on low-end cards. In fact I don't think I've ever seen a GTX 650 with anything better, so it may be a limitation imposed by the GPU and/or NVIDIA.

 

[sheh]

But GTX 650 isn't low-end. I also see some 750s with the same thing. It can't be a GPU limitation, and I don't see a reason for Nvidia to impose this on their board partners.

 

[ViRGE]

But GTX 650 isn't low-end. I also see some 750s with the same thing. It can't be a GPU limitation, and I don't see a reason for Nvidia to impose this on their board partners.

GTX 650 is low end. That's GK107, NVIDIA's lowest end dGPU at the time. And GTX 750 is the company's lowest end GPU of the Maxwell generation.

As for why NVIDIA would "impose" this, I really don't think the board partners mind. It keeps the BoM down in a very competitive marketplace, and since these cards require so little cooling a more complex fan assembly would not be as beneficial. It would be nice to have, but not especially beneficial.

 

[sheh]

Found now that Asus's GTX 650 uses 4-pin, so I guess we can't blame Nvidia after all.

For me low-end would be things like the 630, not 650.