New replacement computer fan reads 0rpm

When I ordered a replacement fan after my old one died with a scream of death (blades locked and wouldn't budge)

The new (package of 3) 40mm 12v fans arrived but they had about 8-10 blades instead of the 7 in the picture and title
Also when turning off they make a plasticy grindy noise when they're about to stop even though they are super quiet when actually running

They also dont have a very high speed and vibrate quite a bit (bad magnetic field proportions?) Even at twice their rated speed and voltage they barely blow a feather around yet vibrate wildly (Dont know how they can survive that)

And they dont have an RPM reading at all. 3rd (tach) wire is there but computer doesnt register any RPM in bios or with speedfan.
They do spin though.

I've tried using a combination of resistors and/or capacitors to create my own "tach" signal but it still doesn't seem to do anything. Still reports 0 RPM and that causes my computer to make a 2nd beep on startup. (Covered beeper with a dab of hot glue since it's ear piercingly loud)

Did I get a batch of reject fans possibly? They have thin poorly constructed blades with a number of physical defects (Factory molded plastic bits here and there)

What would you recommend if I should return these for something else?

The fan is "enough" to cool my CPU but just that alone. (5W CPU with integrated graphics)

Yeah I have a functioning 120mm 2000RPM Case Fan
Speed flucates very little at about 1,700-ish when at full power.. Very good bearings with no defects. Tach reads perfectly except at extremely low speeds

(I saw 16,000RPM as the max speed when it was only going a few hundred rpm in reality) Though it still functions fine. And very silently at 1,000RPM or so.

(Using a custom built fan controller with a 125W darlington transistor and 1K resistor and a potentiometer as voltage divider) A bit overkill of a transistor rating but it was only 1$ for a set of two PNP and two NPN's
To control the speed quickly and as precisely as i need.

No tach reading at all from the chinese fans though.. Not even 1 of them out of the three. They all work. although poorly. Fan speed adjusts properly even though there is no tach reading (0RPM no matter what)

Even If I gave you the link to the amazon page it'd be incorrect as i've gotten a 9 blade 3-pin fan instead of a 7 blade 3 pin fan that was advertised.

And they seem to be really poorly made. Poor material poor construction poor quality. Barely the minimum to work. Only a few visible resistors and single chip on them. (They dont start spinning till over 5v) And they seem to have no trouble running at twice their rated speed for hours without even getting a faint bit warm.

(And still only blowing half what my original computer fan did at half its rated speed!) And these are all 40mm PC Fans. I'll see if i can find the closest picture i can.

https://i.ytimg.com/vi/sCw_nHPOfSo/hqdefault.jpg

http://thumbs.ebaystatic.com/images/...Pdo/s-l225.jpg

It looks nearly identical to these two fans

CPU heatsink is clipped on with 2 metal "hooks" like a northbridge heatsink.. Very small! Probably nothing to upgrade it to.

My computer doesn't have any 4pin fan headers. Only a single 3pin header (Walmart acer computer)
Speedfan is used to adjust the fan control

On boot and at bios or desktop without any speedfan settings it runs at 45% unless I use speedfan to change it

Speedfan correctly controls the speed of either fan. Even though the 40mm fan has no rpm reading it still changes speed to whatever i set. Though it barely blows any air regardless of its actual speed and barely compares to the original fan that came with the computer

It has correct readings for my 3pin 120mm case fan on windows and in the bios

but none of the 3pin 40mm fans have any reading in bios or windows

heres a few of the best screenshots I can find so far

https://i.imgur.com/j9Yh7De.jpg

http://i291.photobucket.com/albums/l...7.jpg~original

http://i.ebayimg.com/00/s/MTIwMFgxNjAw/z/cjUAAOSw9mFWGwTC/$_1.JPG?set_id=880000500F

If you look online its possible you might finder a higher res picture but there literally is zero 4pin fan headers. Only a singular 3pin CPU fan header (Normally under load or not the original fan barely makes a peep and still keeps it cool)