My Cpu cooling fan does not function when ram installed

hello i just built a Desktop and the Cpu fan will not function when the ram is installed and the computer functions. if i put the ram into the 1 or 2 spot nothing happens on the screen but the cpu fan runs at full rpm, but if i have the ram in 3 and/or 4 the computer boots, but the cpu fan does not run it just gives a slow turn then stops for a few seconds and repeats. i have a sabertooth z77 mother board, ivybridge i5, and kingston hyper x ram in two four gig sticks

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Sounds like

The full speed when the machine does not boot is NORMAL. It's a shame the maker didn't explain that.

The other times, it sounds like it's booted and changed to on demand cooling. Didn't the maker document this?

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its more than that

i went into the bios and put the fan on full rpm and it still only give the slow turn, i have no OS in it i have just finished building it. for some reason the fan just does not want to fully turn on.

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Then it's defective.

Time to exchange it.

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i have seen it run when the computer turn on but does not start the boot process. so the fan works, just not when useful

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That only means that it could apply full power.

Later the BIOS switches to a PWM mode and it appears to have failed.

You can recheck your work or bail out by connecting to some +12V supply lead off the PSU but all that is your choice. Note I can't check your work of if the BIOS is current, etc. But it's never worked proper so why would do anything but return a defective product?

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Check out...

What does your manual explain about ram placement. if the ram requires certain location, then follow it. Swapping around among the 4 slots seems rather odd. Though it should within the bios may provide also fine tuning the ram as well. Also, there's the outside chance that some bios/UEFI maybe needed as a last resort to help as it may address the ram issue. At least check it out from the support website.

(ram support)

The fan should under auto-mode select what's best for operation, but since you've already selected hi-speed, that's suggests something amiss if it can't spin or refuses to operate correctly. Again, I refer to mtrbd. setting or issue sif so related. The mtrbd. is also DDR3 ready, I assume you have decent ram to install as well, like a matched pair and hi quality.

tada -----Willy Happy

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still no luck

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