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I need to replace the fan on my graphics card. The original fan is exactly like this one but there is another fan that seems to be a new revision of the same model number from the same manufacturer (NNTG vs. NNTM). The main difference seems to be the shape of the blades:

Neither I nor the DHGate seller can find any data about the fans (CFM, noise) so that's why I ask here.

To make up my mind I need an answer to both questions:

  1. Which blade design is likely to cool the GPU the most?
  2. Which one is likely to be the quietest?

The safe choice would be to get the exact same one (NNTG) but if the new design can be more efficient with the same noise, or as efficient but quieter, I'd prefer the new one.

Note that I don't want to buy an aftermarket fan (even if the prices are similar), I just want a replacement for the old one.

EDIT 2015-04-26 : Finally I bought both and, unlike what I said in the comments, I found a way to quickly switch the fan without taking out the whole heatsink assembly, allowing me to test both fans.

Despite the general consensus that NNTM was supposed to cool the GPU better, temperature with NNTG is actually 5°C cooler than with NNTM (after 10 minutes of running glxgears in full-screen). Maybe the motor doesn't match the power needed for the redesigned blades of NNTM, I don't know.

Anyway, if you need to replace a GA512SL fan for a RadeonHD like I did, buy the NNTG model :-)

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  • $\begingroup$ I don't suppose you'd care to buy them both, do a comparison test, and then share your findings? ;) $\endgroup$ – Air Mar 11 '15 at 18:10
  • $\begingroup$ I thought about it, but switching fans would also mean unmounting the whole heatsink assembly, cleaning/applying thermal paste, etc etc, at least twice. I'd like to avoid that, I already cleaned it up from the old thermal paste (which was all hardened; I rubbed it with a credit card and cleaned with 90° alcohol) and now the board is all clean, just waiting for a replacement fan. Althouhg the results sure would be interesting, I really don't feel like messing up and cleaning the board again two or three times (even if the thermal paste won't be hardened like the old one was). $\endgroup$ – MoonSweep Mar 11 '15 at 18:34
  • $\begingroup$ And, beside spending 40 bucks instead of 20, another reason is that the CPU fan noise would probably cover the GPU's one, so I could accurately monitor the tempearature from the thermal sound inside the GPU, but probably not the noise level. $\endgroup$ – MoonSweep Mar 11 '15 at 18:37
  • $\begingroup$ If you think the difference in noise level won't be measurable, then it's even more likely it won't be noticeable, in which case you probably don't have a reason to measure it in the first place. $\endgroup$ – Air Mar 11 '15 at 18:45
  • $\begingroup$ I thought so, that's why I'd rather trust theory, and ask the experts ;) $\endgroup$ – MoonSweep Mar 11 '15 at 18:55
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Hopefully some helpful observations:

  1. Both fans have the same power rating
  2. Blade size differs I would have thought given the power rating this would equate to the smaller blades having a faster rpm, the larger blades can have a lower rpm for the same air flow.
  3. Rotational speed can be a factor in noise as faster generally equates to noisier, I say generally as not always the case. Larger fans generally have a lower rotational speed and produce less noise.

So to summarise I think both probably have similar air flow specifications, but the smaller bladed fan has a faster rpm, so is probably more noisy than the larger bladed version.

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  • $\begingroup$ It's far closer to an answer than what I got on overclock.net one week ago (which was "just buy an aftermarket fan, it would cost the same", hence the closing note in my question). I'll accept this as an answer if I don't get anything better in the following days. Thanks a lot ! $\endgroup$ – MoonSweep Mar 11 '15 at 17:06
  • $\begingroup$ Best way I am sure someone will be able to make some further observations, a new fan revision would hopefully indicate improvements so maybe the blades profile is more efficient for x,y reason. $\endgroup$ – Ant Mar 11 '15 at 17:11
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Factors determining fan airflow (heat reduction):

  1. Blade pitch.
  2. Blade shape and size.
  3. Motor power and RPM.

In your case 3 is the same, 1 and 2 in the "newer version are bigger", so it will cool better. Main source of noise in fans is coming from the bearing and the electromotor (same in both cases) and from the blades which are slightly larger. Considering that our hearing works on logarithmic scale, I highly doubt that the increase of blades's size in the second model will double the noise, i.e. make it possible to discern from the first. Based on that, draw your conclusion :).

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  • $\begingroup$ So, to summarize: the "newer version" will cool better, but will also be a bit noisier, although that probably won't be noticeable ? As a side note, how do you know the bearing and electromotor is the same in both models ? $\endgroup$ – MoonSweep Apr 12 '15 at 6:09
  • $\begingroup$ The specs are the same (DC 12V, 0.13A) and everything in China is cost efficient, meaning, they probably just made a small design iteration to optimize the product, rather than redesigning it from the scratch. $\endgroup$ – Ziezi Apr 12 '15 at 9:07

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