XPS 9000: Fans speeds up while in BIOS setup?
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From: Nick on 20 Mar 2010 03:08 I've noticed this before, but was too busy to pay much attention. When I hit F2 and go into the BIOS setup on my XPS 9000, the fan at the back of the computer revs up; noticeably faster and louder than most of the time when I'm in Windows, and it doesn't slow back down until I exit setup and the computer starts the rest of the boot sequence. When it happened again a few minutes ago, I notices that my new UPS was also indicating a slightly higher than usual current drain. Not a major increase, just two 'Load' LEDs (out of five) lit up instead of the normal one. The fan also revs up briefly when I turn on or reboot the computer, but I 'assume' that's just normal powering up. My best guess is that the fan speed and power drain increase because some power management function isn't active yet, and the CPU and fan run at maximum speed until the boot sequence is far enough along for power management to take control. So, for all the other XPS 9000 owners out there: do your fans speed up while in the BIOS setup, or do I have another weird issue to puzzle about? P.S.: the new UPS (with a sine wave output) solved my power problems (in another thread); passed a 'pull the plug' test with flying colors. -- Nick <mailto:tanstaafl(a)pobox.com> Clarke's Third Law: "Any sufficiently advanced technology is indistinguishable from magic."
From: Brian K on 20 Mar 2010 03:15 Nick, Which model did you buy?
From: Nick on 20 Mar 2010 05:00 On Sat, 20 Mar 2010 07:15:24 GMT, in alt.sys.pc-clone.dell, "Brian K" <remove_this(a)hotmail.com> wrote: >Which model did you buy? APC's Smart-UPS SUA 1500. Big and not cheap, but it has the capacity and outlets to easily handle one computer, two monitors, two or three external hard drives, and a DSL modem with plenty of run time and nothing winding up on a surge-protected outlet. So when the inevitable power outages happen, I can finish things up at my leisure and wait for the lights to come back on without having to rush to shut things down. -- Nick <mailto:tanstaafl(a)pobox.com> .... And it was written in fiery pixels: FREE UNLIMITED ACCESS FOR ALL!!
From: Cmplx80 on 20 Mar 2010 14:21 Nick wrote: > I've noticed this before, but was too busy to pay much attention. > > When I hit F2 and go into the BIOS setup on my XPS 9000, the fan at the back > of the computer revs up; noticeably faster and louder than most of the time > when I'm in Windows, and it doesn't slow back down until I exit setup and > the computer starts the rest of the boot sequence. > > When it happened again a few minutes ago, I notices that my new UPS was also > indicating a slightly higher than usual current drain. Not a major > increase, just two 'Load' LEDs (out of five) lit up instead of the normal > one. > > The fan also revs up briefly when I turn on or reboot the computer, but I > 'assume' that's just normal powering up. > > My best guess is that the fan speed and power drain increase because some > power management function isn't active yet, and the CPU and fan run at > maximum speed until the boot sequence is far enough along for power > management to take control. > > So, for all the other XPS 9000 owners out there: do your fans speed up while > in the BIOS setup, or do I have another weird issue to puzzle about? > > P.S.: the new UPS (with a sine wave output) solved my power problems (in > another thread); passed a 'pull the plug' test with flying colors. > Most likely, this is normal and is the way the thermal management works. The following is from memory, so there could be some gaping holes: The BIOS has no way of controlling fan speed. This is a function of an OS driver (after OS has booted) and motherboard circuitry. The driver gets the internal cpu temp(s) that are generated by on-core thermal diodes. It uses this info to generate a PWM signal which controls the fan speed. So when in the BIOS--depending on the design--the default (before OS) fan-speed signal may be a full voltage (12v) resulting in max fan speed or possibly 2 or 3 speeds driven by rather course temperature steps. If you have a temp monitoring program installed (like Core Temp), you will notice that right after boot-up, the temps are rather high, gradually decreasing to their OS idle states. If I recall, this has been the approach since the Pentium IV days. Frank
From: Larry Hermann on 20 Mar 2010 22:40
I haven't tried going into the BIOS, but the fan on my 9000 is audible for about ten seconds on cold boot and again on shutdown. Now I know why. Larry "Nick" <tanstaafl(a)pobox.com> wrote in message news:i8r8q5tlbkqifljl8l4m9ccni8tkmlc3nd(a)4ax.com... > > I've noticed this before, but was too busy to pay much attention. > > When I hit F2 and go into the BIOS setup on my XPS 9000, the fan at the > back > of the computer revs up; noticeably faster and louder than most of the > time > when I'm in Windows, and it doesn't slow back down until I exit setup and > the computer starts the rest of the boot sequence. > > When it happened again a few minutes ago, I notices that my new UPS was > also > indicating a slightly higher than usual current drain. Not a major > increase, just two 'Load' LEDs (out of five) lit up instead of the normal > one. > > The fan also revs up briefly when I turn on or reboot the computer, but I > 'assume' that's just normal powering up. > > My best guess is that the fan speed and power drain increase because some > power management function isn't active yet, and the CPU and fan run at > maximum speed until the boot sequence is far enough along for power > management to take control. > > So, for all the other XPS 9000 owners out there: do your fans speed up > while > in the BIOS setup, or do I have another weird issue to puzzle about? > > P.S.: the new UPS (with a sine wave output) solved my power problems (in > another thread); passed a 'pull the plug' test with flying colors. > > -- > Nick <mailto:tanstaafl(a)pobox.com> > > Clarke's Third Law: "Any sufficiently advanced technology is > indistinguishable from magic." |