![]() ![]() Click on the plots for full-sized versions. (Note: The label on the X-axis should read “Time (mm:ss)”, but I’m too tired to go back and change it now. This cycle is apparently unaffected by CPU temperature: On the new fan, it drops the fan speed in increments of 75 RPM until it gets below the threshold, then spins it back up to a much higher speed and repeats the process. After collecting 5-10 minutes of data at idle, I started a program that fully loaded the CPU for several minutes, and continued collecting data until the system returned to a stable idle state. I ran this experiment on the PE 830 (Pentium D 940, 3.2 GHz, 130W TDP) and the PE 840 (Core 2 Duo E6400, 2.13 GHz, 65W TDP).Īs it turns out, the BMC isn’t intelligent enough to vary the speed of the fan based on CPU temperature. I wrote a script to collect fan speed and CPU temperature every 2 seconds. I ran an experiment to try and determine how fast my fan needed to run to be effective. That wouldn’t be a problem, except that Dell was cheap on all of their tower chassis in the mid-2000s and made the back case fan do double duty as the CPU fan. The fan I bought pushes 74 CFM at full speed the OEM fan managed 150 CFM. Bad news: loading the machine runs the core temp up to 60C (Intel says to keep it below 63). I pushed the wire all the way through the connector and bent it over, which should keep everything in place. I couldn’t shove the stranded wire into the new fan’s connector, so I soldered some solid wire from a bit of spare CAT 6 cable onto the leads. I lopped the connector off of the original fan (at least it’s not a non-standard pinout on a standard connector). This is already documented in several places on the web, but just to get it up here one more time: Signal ![]() Now, before I could replace the fan, I had to deal with Dell’s custom pinout (because their 4-pin arrangement is clearly superior to the standard 4-pin arrangement that carries the exact same signals). The script was able to parse the BMC firmware update for the PE 830, so I went ahead and ordered a new fan. I downloaded that guy’s Python script and ran it on my PE 830. TLDR the thresholds in used by the BMC can only be changed by hacking the BMC firmware update package. Of course, because this is the Internet and I’m not the only hacker who likes to play with hardware, someone else had already solved this problem. Unfortunately, I also found that the slower fans often trigger the “Lower Critical Threshold” (they spin too slow), causing the BMC to spin them up, which gets me back to the noise problem I had in the first place. I determined after some Googling that most people solve the problem by replacing the system fans with slower, quieter, models. My first thought was that I might be able to control the fan speed, but fan speed is firmly under the control of the BMC (Baseboard Management Controller) I can’t control it from software. The SC 430 is reasonably quiet (Dell based it on their Precision platform), but the other two, the 830 and 840, are just loud enough to be annoying. Dell doesn’t go to the same trouble when they design their servers. I’m used to desktop machines they’re designed to run quietly enough not to annoy someone trying to work in the same room. One thing I didn’t think about before I got them was how much noise they might make. Put the USB into the server, boot to the BIOS Setup F2 and make sure USB is enabled with BIOS support and that it is at the top of the boot sequence.A couple of weeks ago, I acquired three old Dell servers to play with: a PowerEdge 840, PowerEdge 830, and a PowerEdge SC 430. We'll also assume your USB is assigned the drive letter G: after formatting. To check to make sure, in diskpart type "list disk". ![]() For this example, we'll assume it is letter F. Mount the 2012 ISO (just double-click in Windows 8 and later), take a note of the drive letter. Extracted files must be copied to a specially prepared flash drive. you can't just put the ISO on a flash drive. DVD drives were still optional when the 1950 was sold, and a CD drive will NOT read Server 2012 media (Vista/2008 and later is DVD only).įor a bootable USB. circuitry installed, even if your sensor chip supports pwm. Note that many motherboards do not have pwm. You can't just put the ISO on a DVD.Īlso, make sure that your 1950 has a DVD drive. pwmconfig revision 6166 () This program will search your sensors for pulse width modulation (pwm) controls, and test each one to see if it controls a fan on. If you are using Windows 7 or later, just right-click the ISO and choose Burn Disc Image. ![]()
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