GA-P55-US3L: strange fan header voltages and help needed with some BIOS settings

[runn3R]

Hi forumjoe

SYS_FAN2 has smart fan control. It is automatically set as enabled by design.
The speed of this fan depends on system temp, not CPU temp. It has only voltage control.

[forumjoe]

Ah, well, if I've understood correctly what you've now stated, runn3R, that would explain why I could never get my inlet fan to run if I had it connected to Sys Fan 2 header. From system power-on, the internal temperature of my P55-US3L-based PC would have been well below the probable system temperature that would have turned that fan on.

I did try it initially with Smart Fan Control enabled in the BIOS, and also tried both modes, including voltage control, but I was still unsuccessful in getting the fan to run at all. From what you state, even if I were, it'd run at a speed entirely determined by the motherboard, not by me - unless it's somehow controllable via the EasyTune utility or something.

For my purposes - and I guess for a lot of other people's as well - this Sys Fan 2 header connection is all but useless. That's why I now use my inlet fan on the Pwr Fan header instead. As for Smart Fan control, it's a shame that I've had to ditch using that as well. I think that with cooling and quieting requirements as they are now, with PCs, people prefer to have more direct control over the speeds of the fans, rather than leaving it to the motherboard and temperature-sensing. I think that people would rather have all connected fans running from power-on, and so then know that that's the maximum amount of noise the fans are going to make. It would have been very nice if, with Smart Fan control, one could just use the BIOS to set an individual source voltage for each fan, in the range 6v - 12v. Instead, I've had to do it on the three fans I use by my own hardware mod.

[Dark Mantis]

That does explain quite a lot actually. It also confirms that my suggested course of action of running all the fans from a Fan Controller is probably the best way.

[forumjoe]

Yes, in the end it comes down to a choice of this:

(i) Use all three fan headers on the motherboard in combination with the BIOS's Smart Fan Control and accept that the speeds of them will be determined by the motherboard and will be temperature-dependent;

or (ii) Ignore and disable Smart Fan Control and instead use, inside the PC casing, independent voltage controllers for each fan, re-wiring to the headers from the controllers where necessary;

or (iii) Ignore and disable Smart Fan Control and instead install a purpose-designed multi-fan controller into the frontpanel of the PC and use that to control the fans.

[Dark Mantis]

Yep. That's about the size of it  I guess.

[runn3R]

Ah, well, if I've understood correctly what you've now stated, runn3R, that would explain why I could never get my inlet fan to run if I had it connected to Sys Fan 2 header. From system power-on, the internal temperature of my P55-US3L-based PC would have been well below the probable system temperature that would have turned that fan on. I did try it initially with Smart Fan Control enabled in the BIOS, and also tried both modes, including voltage control, but I was still unsuccessful in getting the fan to run at all.

You can try to use different system fan which can rotate when voltage is around 5,4 V as the one you have now can't start at all at this level unfortunately.

For my purposes - and I guess for a lot of other people's as well - this Sys Fan 2 header connection is all but useless.

For sure you can find a fan which will rotate with this header. As it depends on the system fan if speed control function is supported.

I think that with cooling and quieting requirements as they are now, with PCs, people prefer to have more direct control over the speeds of the fans, rather than leaving it to the motherboard and temperature-sensing. I think that people would rather have all connected fans running from power-on, and so then know that that's the maximum amount of noise the fans are going to make. It would have been very nice if, with Smart Fan control, one could just use the BIOS to set an individual source voltage for each fan, in the range 6v - 12v. (...)

Thanks for your valuable input.

[forumjoe]

Yes, I suppose I could have tried the one other 'standard issue' inlet fan of the same size that I had, but I'd actually very carefully picked and purchased my various fans for their very low noise performances. Therefore, I had to accept whatever minimum working voltage they each had. For anyone who truly cares about reducing fan noise - and, these days, that's a fair proportion of PC users - it's the mechanical design of the fan and the amount of noise it produces at various revs that matters, rather than the precise voltage at which it starts to work. Most technically-minded persons wouldn't expect a fan of this kind to work at a voltage as low as 5.5v or thereabouts.

If anything, I think my and others' experiences with Sys2 fan header points to Gigabyte having assumed too low a turn-on voltage for the typical fan. In other words, that particular header needs to produce at least 7.0v in order to ensure adequate start-up on what could be a very wide assortment of nominally 12v fans.

As I remarked before, though, I think Gigabyte would have saved everyone a lot of aggro and disappointment if they'd not designed that header output for half or some other fixed low speed, even though it was also temperature-dependent. Instead, they should have organised Smart Fan Control in the BIOS so that it was able to independently control each of the fans via user-adjustable voltage control, in the BIOS. For each fan, temperature-tweaking for speed could have been a further option in Smart Fan Control. As it is, it rather looks as though Smart Fan Control has been totally wasted for the more noise-conscious of us. And particularly with Sys2 fan header being unusable, that's a big loss in choice of fan control.

Anyway, I hope that my discussion of the various fan headers has made their operation clearer for P55 board users.

[fadsarmy]

Yes, in the end it comes down to a choice of this:

(i) Use all three fan headers on the motherboard in combination with the BIOS's Smart Fan Control and accept that the speeds of them will be determined by the motherboard and will be temperature-dependent;

or (ii) Ignore and disable Smart Fan Control and instead use, inside the PC casing, independent voltage controllers for each fan, re-wiring to the headers from the controllers where necessary;

or (iii) Ignore and disable Smart Fan Control and instead install a purpose-designed multi-fan controller into the frontpanel of the PC and use that to control the fans.

That does not solve the problem, it is just a workaround. This is NOT acceptable. Gigabyte have been making motherboards long enough to know that every fan which is bios controlled needs a minimum start voltage. Most fans need a minimum of 6v to start. If the bios is only providing 4v then the fan isn't going to run. I experimented with over forty fans and not one would run with bios fan control enabled. In the summer this isn't a problem because the sytem temp is sufficient to supply the start voltage. I woke up at 4am today and when I switched the pc on it resulted in the siren being triggered because the fan wasn't receiving enough voltage at 25 C.

Personally, I think this a joke. There should ALWAYS be a start voltage of about 6.5 to 7v, even at -10 C  in Antartica, to avoid this.

Gigabyte have gone backwards. I use to have more control ocer My K8NMF9.

I am going to mod my bios bios and fix this.

[forumjoe]

Yes, you're right, my three options do not SOLVE the basic problem. They're merely workarounds. I wasn't claiming anything different.

I agree wholeheartedly with your view of Gigabyte and how they've so badly dealt with the Sys2 fan header output voltage. With several revisions of that particular board having already been issued, you'd have thought they'd have fixed it by now. From what I've been hearing, other boards in the P55 series have the same problematic header.

I found it extremely annoying that that particular header was not dealt with in a sensible manner by Gigabyte. As it stands, that Sys2 header and its associated electronics on the board are a complete waste of real estate and of that fan's inclusion in the BIOS. But it might be that Gigabyte can't now easily change that bit of hardware on the board. It was fortunate that, in my case, I was able to make use of the Pwr Fan header instead.

As you'll know from the thread, I've got around the general problem of all the fans usable on this board by using Fanmate fan controllers and just manually setting the speeds of the fans to fixed values. This is okay for me but might not be a satisfactory solution - sorry, workaround - for others.

I've had the feeling that Gigabyte tried to be a bit too clever when they devised the Smart Fan Control. For me, that's now completely wasted, as is also the Sys2 fan header. With a tad more thought, they could have organised the board and Smart Fan Control to give full user control of each and every fan, together with optional temperature control of the fans. What they came up with instead is perhaps just a hurried, ill-devised arrangement to suit what is, after all, a comparatively inexpensive board.

[runn3R]

(...) Sys2 fan header (...) needs to produce at least 7.0v in order to ensure adequate start-up on what could be a very wide assortment of nominally 12v fans. (...)

(...) There should ALWAYS be a start voltage of about 6.5 to 7v, even at -10 C  in Antartica, to avoid this. (...)

Please try this special FV bios for your issue.

[forumjoe]

Thanks, runn3R, for posting the FV BIOS. I'm afraid it's a bit too late for me (Forumjoe), though, as I've now made considerable hardware alterations to get around the problem and am on the very point of installing Windows and all my software for the first time on this mobo. I would nevertheless urge anyone else who's encountered the 'header problem' to perhaps give BIOS FV a try. Maybe if the changes now made to the BIOS in respect of these fan headers have significantly improved the situation, I myself will later undo the hardware mods I've made and will try the headers with the revised BIOS. Perhaps someone could post a jpg of the revised BIOS settings later in this topic?