W230ST/NP7330 Quieter Fan HardMod

Why did I do this?
Just got the machine a few days ago after waiting about six months before throwing down the cash. This is the ultimate middle ground between my Samsung S7 Slate and my overkill 1kW desktop. The only thing wrong, and which I could not get used to, was the sound level of the fan in full on gaming. It was just way too loud for me to keep the machine. So either I had to return it or try to mod it, and I didn't really want to give up such a beauty of a machine just because of one bloody problem!

What is this mod?
Just a very simple mod which lowers the 5V PWM feed to the fan to about 4V, which is still more than enough to run the fan at 'almost' full whack. The noise level dropped substantially enough to be fully acceptable now by my picky standards.

What can go wrong?
I suppose I won’t be able to play original Crysis at max settings and full rez since it would start to throttle more than without modding it. But since I’m okay with not maxing everything, the hugely reduced angry fan noise far outweighs this. But that might not be to your taste.
NOTE: The 1N4148 is rated at max If = 300mA. Even though the fan’s max current is 400ma at 5V, with the reduced voltage to the fan, the current drops to about 320mA max. This is max current (which means not-often, rarely) so the diode is quite okay with this, especially since it’s well placed in the air flow!

*** WARNING ***
Do NOT attempt this if:
- You have never used a soldering iron before
- You run the machine so hard that it throttles, a lot
- Worried you might not be able to reverse the procedure in future when your machine needs servicing (warranty woes)
*** WARNING ***

Here's the procedure:
1. Unscrew back panel - three screws.
2. Unplug fan (red arrow in pic), then unscrew the three fan mounting scews (yelllow arrows in pic).
3. Remove the fan, flip it over, peel back the green sticker then carefully cut a small slot above the red wire in the circular black insulating sheet wedged between the PCB and chassis.
4. Solder in a 1N4148 (or 1N4001..7) diode inline with the fan's positive feed (be careful of polarity).
5. Put some insulation on top of the mod (plastic black rectangular sticker in pics).
6. Reassemble everything (going backwards)

Further Ideas
1. Add an override switch, if you need to dual-purpose the machine, say in a quiet office environment and also need it as a loud 'gaming rig'. Just run a thin two-core cable, parallel with the diode, to a tiny switch on the machine to toggle it between quiet and TURBO! I didn't go for this since I only really need this machine for occasional comfort gaming, but mostly programming (this thing is a beast compiling C++ ! ).

2. Instead of a diode, use 2x 6.8ohm 1/4W resisters in parallel, or try some other values to tweak as desired.


The machine now runs much quieter and barely throttled that much under my normal usage. I'm running the Prema 1.1 bios mod with 'turbo disabled' (major thanks Prema - you rock dude!). This is fine for me as this is 2.9Ghz baseline i7-4600, which is plenty speed for everything I need without ever popping the 37W TDP. Also, down-volted by -75mV (thanks HTWingNut - you rock too!) Seems stable so far (froze at -125mV). See Intel XTU shot for what it looks like after editing this post (photo5) and when stressing it (photo6). And yes that is a lot of throttling the last pic, but most of the games I've played so far aren't that brutal .

Hope you found this an interesting read at least .
Regards, ever the
Optimiser!