Hoody_s13 Posted February 15, 2011 Posted February 15, 2011 Hey all I've just recieved my GT 1850's in the mail for my H70. First powerup noticed how much quiter they are compared to the stock fans, and my temps under load with linx runs seem to have dropped a 1-2 degrees on average. I'm running these two off the cpu fan header with a Y-splitter, the one that came with the H70. Quick google search said this wouldnt be a problem with these low draw fans. I checked out my fan monitor in bios and noticed the fans (or whichever is giving the reading) is running at 1750 instead of the rated 1850. Since the fans are running through a radiator, im guessing this is normal, or are the fans running slightly underpowered with the splitter? Share this post Link to post Share on other sites More sharing options...
smduff Posted February 15, 2011 Posted February 15, 2011 They will run slower sharing the same power source, move one to a different header. Share this post Link to post Share on other sites More sharing options...
Hoody_s13 Posted February 15, 2011 Posted February 15, 2011 Just did a quick test, leaving fans attached to the rad and running each individually through the fan header, both read out the same fan speeds at 1750 rpm. Havent removed the fan from the rad to test but I'm guessing the slower speed is because the fans are loaded trying to push air through the dense fins. Wanted to mention too, I've been using a 120mm DEMCi magnetic fan filter since my H70 is setup as intake. With the original fans, simply adding the filter you could hear the fans became a lot louder. Doing the same tests on these GT's, does nothing, and there damm quite to begin with. Share this post Link to post Share on other sites More sharing options...
Locutus Posted February 15, 2011 Posted February 15, 2011 You might want to hook them up to a fan controller or the sys_fan pins on your motherboard and try raising the voltage. It sounds to me like they aren't running at full speed. Share this post Link to post Share on other sites More sharing options...
VaporX Posted February 15, 2011 Posted February 15, 2011 Even if the speed was at spec the air movement would not be. The reason is the back resistance created to the airflow by the radiator. This could BTW account for the speed reduction. That is why fans used on raidiators should not be about CFPM but rather the actual air pressure they can push. Unfortunately most fan companies do not rate the pans in pressure. Share this post Link to post Share on other sites More sharing options...
sticknstone Posted February 16, 2011 Posted February 16, 2011 Since the fans are running through a radiator, im guessing this is normal, or are the fans running slightly underpowered with the splitter? The only way it would be the y-splitter is if there was not enough amps flowing in the circuit. I highly doubt that considering these fans run on about 0.11-0.4 amps Havent removed the fan from the rad to test but I'm guessing the slower speed is because the fans are loaded trying to push air through the dense fins. This statement is 100% true. The amount of cfm reduction is related to the amount of pressure drop the rad causes. Share this post Link to post Share on other sites More sharing options...
BluePanda Posted February 16, 2011 Posted February 16, 2011 I wouldn't worry about 100 rpm, clearly they are moving more air and are quieter. I wouldn't obsess over it if the temps are better. Share this post Link to post Share on other sites More sharing options...
The_Slayer Posted February 16, 2011 Posted February 16, 2011 Slow by 100rpm isnt really a big problem.. I would imagine that fans would have some fluctuation in the RPM and wont spin at EXACTLY 1850 RPM. Also, using the splitter that came with the H70, only one fan will be reporting the RPM. If you look at the splitter, one end has 3 wires and the other has 2. Share this post Link to post Share on other sites More sharing options...
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