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- HP Z400: CPU FAN Noisy after BIOS update

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06-04-2018 09:57 PM - edited 06-04-2018 09:58 PM
I Bought this HP Z400 a used one. Previous owner upgraded the CPU to Intel Xeon W3690 @ 3.47GHz.
He also change the CPU fan and connected to the 4 pin connector near to RAM. (every boot F1 need to use)
Now i decided to upgrade the BIOS to the latest BIOS in HP site 2018.
I notice now my CPU FAN IS NOISY. I tried to control it in BIOS Thermal menu IDLE FAN to the lowest. It will slowdown in few seconds but will comeback to the noisy speed. Please help now what can i do to reduce the noise.
i tried restoring the old bios but no success.
i tried FANSPEED software but no fan control.
Let me know all options
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06-05-2018 10:33 PM - edited 06-05-2018 10:54 PM
That looks like it would make quite a racket even before your BIOS upgrade. That clearly is not a HP heatsink/fan, and has a push/pull set of two fans that look like 80mm ones. Can't tell if it is even plugged into the motherboard header meant for that.
Regardless, I'm recommending you spend the 27.00 to buy an official HP Performance heatsink/fan made for the Z400. Look in eBay for 463981-001, and the lowest price including shipping is 27.00 from a seller who has more than 10. My recall is that uses a 92 x92 x25 mm fan, and I use those heatsinks in all of our Z400 builds. They run so quiet that I cannot hear them from about 4 feet away. It is running at 1292 RPM per free HWMonitor, from CPUid.com. It has the proper pin 1 to pin 5 ground jumper wire, shown:
A tip: when you screw down the 4 screws for the heatsink, assuming you do this, be very careful to not over tighten. The sheet metal threads those go into are under engineered and you can strip the threads easily. Stop when you feel the beginning of things bottoming out. You might want to even put a tiny bit of fine quality thread lubricant on, wiping off almost all of it before starting the process. Who has a micro-torque wrench? Just be very careful.
Some of the fans I mentioned you can buy on eBay are listed as for the Z400 and Z600 performance heatsinks, but that is incorrect. Those fans are thinner and made for the Z600/Z800 performance heatsinks. The Z400 heatsink fan is thicker. Both are 92x92mm square. Buying only a HP fan is a moot point seeing your current heatsink... just get the real heatsink/fan combo.
06-04-2018 10:20 PM - edited 06-04-2018 10:27 PM
1. Read up in the forum here on version 1 versus version 2 Z400s. You know you have a version 2 Z400 if you have 6 instead of 4 memory slots. Nice that it is that easy. There also is a BIOS boot block date you can see, but if you have 6 slots you have a v2 motherboard.
2. Good on you for upgrading to the latest BIOS. I have done that also and have not noted a loss of functionality in our Z400 or Z600 workstations. The original hack of the hardware did not pass the sniff test of the new BIOS, and it defaults to high speed if it senses anything is off.
3. Your best path to good function is to buy the correct HP heatsink/fan for the processor. Your processor is HP certified for that version 2 Z400 workstation.
4. To do that go onto eBay and search for 463981-001. There are two there with the same number but one has more metal and one more black plastic. Both will work. The more black plastic one is a bit newer design. Those are about 30.00 USD here now. You'll need to remove whatever he put in place and place the correct heatsink/fan with proper cleaning of the processor and re-paste of it. I use Noctua, and have for years. Small dab will do ya.
That is a "Performance" level HP heatsink/fan rated to cool up to and including a 130W max TDP processor, which is what the W3680 and W3690 are.
A remote possibility is unlikely: There is an ambient air temp sensor embedded in the on/off switch cable that if it goes bad will be sensed by the motherboard's firmware as being off...... and result is high speed too.
06-04-2018 10:34 PM - edited 06-04-2018 10:36 PM
Take a close look at what heatsink you have. It may be the original, and maybe all the original seller did was change out the HP fan for another type of fan.
Look on eBay to see the HP labels on the heatsink so you know what to look for. I can pull off a HP fan from a spare official Z400 setup and get you the correct part number for fan only. That info is on the label that faces the heatsink so the fan has to come off to see it.
The Performance fans here have 5 pin plug with a ground jumper wire from pin 1 to 5. Pins 1-4 are conventional PWM fan wiring. HP engineering put a lot of tuning into the ecosystem of the fans in their motherboards, and you can't do much better than them. The only thing I do is dink a bit with some Noctua 4-wire fan adapters to drop the voltage a bit on very specific too-fast HP fans I have identified over the years.
06-04-2018 11:16 PM
There is the heatsink, and the fan. The fan has the connector, not the heatsink. One can take a non-HP 92mm fan and screw it on to a HP Performance heatsink and maybe get what you have.
You asked for cheap.... buying a used correct HP 92mm x 92mm x 25mm fan is cheapest. Personally I'd go all-in and splurge the whole 30.00 USD.
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