Quiet ML350 G6 – It is possible

I recently purchased a used ML350-G6 from eBay, to replace the aging server I run that currently hosts Microsoft SBS2011

I bought this machine because it met a number of criteria, reasonably powerful (2 * Xeon E5620, 38Gb RAM, support for plenty of storage), tower case setup, and not too expensive. I was surprised just how much used enterprise kit you can get for a few hundred pounds on EBay!

However, it had one issue, it still far too noisy to use in my home office, where it was going to be placed just a few feet away from where I work.

I’d previously looked at a DL160 G6, but the noise from that was horrendous. To be fair it is designed purely for rack / data centre use, where noise would not be an option, and I’d hoped from what I read that the ML350 would be a lot quieter. It was certainly quieter, but not enough. I wanted something that would not be a distraction when I was trying to work.

When I tried the DL160 that had 6 internal fans that generated a lot of noise, but the loudest of all was the fan in the PSU.

I noticed that the same PSU in the ML350 ran almost silently, I presume that this is because of extra space for ventilation around the PSU in the ML350 case allows the PSU fan to run at a much lower speed.

Looking inside the ML350 I found that it was fitted with 3 120mm fans, with space for a 4th, and these were making all the noise.

I checked out the temperature and fan speeds using the ILO 2 on the system, and it showed that the 3 fans were running under no load at 25%, with CPU temps at a base 40C.

When I stressed the system by running SETI across all 16 cores, both the fan speed and CPU temp rose, and so did the noise

So, first steps were fairly standard, I removed the CPU coolers, cleaned the CPU and cooler surfaces, and put new good quality thermal paste on. I also got a 4th fan to fill the empty fan slot.

With that done, ILO 2 showed that the 4 fans ran at 21% under no load, and the CPU temps still ran at 40C. However when under SETI load what I found was that the fans stayed at 21%, and only 1 of the CPU temps moved off 40 to 45C.

So, 4 fans and some decent thermal paste are worth doing before anything else, and this does reduce noise a bit.

Although the 4 fans running at 21% were a little quieter than 3 running at 25% it was still much louder than I wanted, so I decided to look to see if I could replace the stock fans with quieter replacements.

This however is where the fun starts, below is a picture of the 5 pin header on the original fan, compared to a standard 4 pin header on a PWM fan that fits most standard motherboards.

The original fan is Black, Black, Red, Yellow, Green, where a standard one is Black, Yellow, Green,Blue

After some googling around I found one site that suggested that the fans on an earlier ML series machine (which had different coloured wires) was in fact still using PWM and speed sensing the way a standard fan does, and that the two blacks are just linked together.

A quick test with a meter confirmed that the two blacks are just linked together, so I got a simple 5 pin connector, and rigged up some wires from the standard 4 pin header, to the five pin, with the blacks connected together, and used that in place of the number 4 fan on the motherboard, to see if it would work.

And …. success

The motherboard recognised the standard fan, and the fan speed increased / decreased along with the other three during the boot process.

So, next step was to get some quieter fans, and make some decent connectors to link them to the motherboard.

I opted for some fairly economical Artic F9 PWM fans, nice and quiet, and fairly cheap to boot. I also bought some DuPont crimp sockets, and 5 pin header plug housings to make the new connectors with.

This is the Artic F9 alongside the stock fan removed from it’s housing. You can see the clearly visible smaller motor housing, which increases the space for airflow, allows the fans to rotate slower, and decrease the amount of noise generated per cfm of airflow.

So, having got the bits the first step is to cut oof the standard header of the new fan, strip the cables back a bit, tin then, and get the crimps and connector block ready.

The crimps need to be soldered on to ensure a good quality connection, hopefully your soldering is nicer than mine!

Fold down the top edges of the crimps, and repeat for the other wires, remembering that you need to link the black together to make two crimps.

Once those are all ready, just mount them into the new header.

And that’s it, ready to install.

When installing you need to note that the new headers don’t have the slots like the old ones to ensure that you put the connecter the right way around on the motherboard. So, when you do it, take the old connecter off noting which end has the two blacks before putting the new connector on.

Also, make sure you take a note of the fan airflow direction, you need to make sure that you’re still pushing air in the right direction.

Once I had replaced all 4 fans on the ML350 I again tried a SETI stress test.

Again, even with both CPU’s maxxed out the fan speed stayed at 21%, CPU temp only increased a little on one CPU, and ILO 2 reported everything healthy.

But, best of all, it was running whisper quiet. I literally had to put my ear to the back of the unit to hear the fans / airflow.

At this point I’ve been running this configuration 24-7 for a couple of weeks without any issues.

Obviously, I have to say, this worked for me, but it does involve some messing with your unit, and fitting non OEM parts that you have fitted new connectors to. If you not happy doing any of that, and risking that it may not work on your machine, then please do not try this!