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G5 ML115 cooling problem

Pawel256
Occasional Visitor

G5 ML115 cooling problem

Hi
I just replaced the stock fans in my newly bought ML115 Opteron Quad server. The computer shuts down after a few seconds and I think it is due to low RPM of the fans.

It beeps 3 times during startup, instead of 0 with stock fans.

BMC system event log says:

Lower critical going low, asserted
(Rear Fan and CPU fan - 2 events)

The server sits in my bedroom and it really has to be quiet (hence low RPM fans which run with PWM 800-1800 RPM)

These fans with 35 CFM @ 1800 RPM / 19dBa should be more than enough for a 75W processor.

Is there any way of changing the lower critical? Or disabling the function?
5 REPLIES
u84823
Regular Advisor

Re: G5 ML115 cooling problem

I'd be nervous about changing the fans, the chipset in that server runs VERY hot even with the standard fans. Also note the CPU fan draws air up through the heatsink (more usually the blow down through it).
Jason404
Advisor

Re: G5 ML115 cooling problem

@Pawel256:

Did you replace the fans with PWM fans with 5-pin connectors?

Did you have any luck with making the ML115 G5 any quieter in the end?

Were you able to change the acceptable ranges, or turn of the Shut Down event?

I really want to make my ML115 G5 a lot quieter as well.
Pawel256
Occasional Visitor

Re: G5 ML115 cooling problem

Hi

I tried different fans with both 4-pin PWM and standard 3-pin connectors

I made my ML115 quieter buying two 120mm fan adapters for CPU and System and installing fixed speed 1100RPM 120mm fans.

I was unable to change the acceptable range, which according to my experiments is 1000. Should a reading from any of two fans be lower than 1000 at any point, the computer would shut down immediately.

I think the best solution is to get some quiet fixed-speed fans with high CFM and >1050RPM. Just make sure you get an extra fan for the bridge, which can get really hot once you replace the stock "hairdryer" CPU fan.

I don't think my 120mm fans are particularly effective (the case is too small for them). High quality 80 and 92mm 3-pin should do the trick.

You will have to decide between high CFM and low noise. Those quiet and effective ones are usually very pricey. I'd go for about 14dBA if you want them quiet.
Dr Mabuse
Occasional Visitor

Re: G5 ML115 cooling problem

Hi,

Could you provide any more detail on the fans you ended up fitting? Such as links?

My server sounds like a jumbo jet.
Jason404
Advisor

Re: G5 ML115 cooling problem

@Pawel256

Thanks for your reply, and sorry for not replying before. I got distracted, and I have still not made my ML115 G5 quieter.

You are the first person that I have found on the entire internet that has managed to make their ML115 G5 quieter. I am thinking of making a webpage to help other people do this once I have done it myself.

Do you mean that you kept the original heatsink part of the CPU HSF and just replaced the fan? I am thinking of replacing the whole HSF. Even though it is a AMD processor, the mounts appear to be the same as for Intel S775, so I am going to try fitting a S775 quiet cooler, with a PWM fan that does not go slower than 1000RPM. Finding a suitable one is proving difficult. I prefer to use PWM for the CPU fan.

I think I will fit a fixed speed slow speed fan that runs higher than 1000RPM, as you suggest.

So you fitted a third fan for the bridge? Is that really needed? Which one did you use?