Delta-80mm

[Kunal]

I've had a 68CFM Delta-80mm on my HS (AlphaPAL8045) for quite some time now, and have to say I am impressed with the temps. But I was browsing some hardware retail sites(UK), and they mentioned that the fan shouldn't be plugged into the motherboard fan adapter for the HSF. Any reason why?

(I believe it draws about 6.9w)

[KILLorBE]

At 12V 6.9WATT it draws about 0.575 Amp. which is slightly more than most fan headers can handle, Mine can handle 0.5 Amp. MAX. but I've also seen some that can only handle 0.2 Amp.

I suggest you change the wiring, or cool the FET's.

By active cooling the FET's you might be able to draw some more (could go up to 1 Amp, but that depends on the type of FET used).

Also, but I'm not sure, some boards allow you to draw 0.5 Amp per fan header (like mine) that could be because they use separate FET's for each fan header, or because they use one massive FET for all fan headers, if the last is the case you may not have to worry (*EDIT* if you only use 1 out of 2 or 2 out of 3 fan headers), tho the PCB might not like it (The traces could burn).

Hope this helped

[Yodums]

The follow up was correct.

The fan header only supports to maybe 4watts where plugging maybe 4.44watts will kill the header.

With Deltas no one recommends you putting it in the fan header always to the PSU and use the RPM sensor method if you really need it.

Yodums

[Hoot]

The limitation of .5A per header is not because of the voltage regulator, but merely the ability for the header pins and traces to pass that much current without overheating and deteriorating. You will be better served to run as many of you fans as possible off of an unused 4-pin Molex connector.

73, Hoot

[hammy1]

In UK where do u get Alphe fans from.

[SickBoy]

My Delta 68 came with the power leads already split - power goes through a 4 pin connector and the RPM wire is in a 3 pin connector for monitoring.

[KILLorBE]

Originally posted by hammy1
In UK where do u get Alphe fans from.

I guess you mean Alpha HSF's, you could try one of these:
http://www.aria.co.uk/
http://www.overclockers.co.uk/ direct link to Alpha HSF's (http://www.overclockers.co.uk/acatalog/Online_Catalogue_Alpha_CPU_Coolers_28.html)
http://www.overclock.co.uk/
http://www.theoverclockingstore.co.uk/index.php

You also might wanna try www.OC-shop.nl if you want a PEP66, cuz they're ~$20 at the moment w/o fan.

[hammy1]

:)

[Kunal]

Hmm.... so I've been stressing my mobo then ;) I've got some spare 4pin connects I'll have to hook it up.

Would this explain why the RPM monitor was being eratic? 4850-5200rpm variance?

Actually... i think I'll hook it up to my rheobus and turn it down. see what optimum speed/sound balance I can get :D

[Kunal]

Well I hooked the delta upto my rheobus, but kept the RPM monitor plugged in to the mobo.

Turned up full the delta only does 4688RPM, when it used to spin on average around 5k RPM. Anyone noticed something similar on their setup?

I've set the Delta to 3500RPM, so it's not so noisy for night time now, and it keeps the rig at38degC idle (not sure what load is yet, although still under 50 so nothing to sweat over.)

Could the rheobus be causing the lower RPM's?

Should I just buy a normal rheostat for the delta and not use it with the rheobus?

[KILLorBE]

Nah thats normal, a fanbus that puts out the same (well almost the same, about 0.2-0.5V less) voltage as the input is very expensive.

If its still able to keep your CPU cool I would keep it.

It spins at lower RPM because it receives less voltage due to the resistance.

You could put a switch on it so you're able to switch between the rheobus, off (not a good idea:p ) and 12V. (just use a switch to choose between rheobus and 12V).

[Hoot]

Originally posted by Kunal
Hmm.... so I've been stressing my mobo then ;) I've got some spare 4pin connects I'll have to hook it up.

Would this explain why the RPM monitor was being eratic? 4850-5200rpm variance?

Actually... i think I'll hook it up to my rheobus and turn it down. see what optimum speed/sound balance I can get :D

No, the 12V coming out of your PSU will vary a little (and hence fan speed) as a function of the amount of load you have on the +5V output. When your CPU is loaded and more current is being drawn from the +5V, the +12V will go up (and hence fan speed). At idle, the +12V will be at its lowest. This is an unexpected benefit since you normally need all the speed you can get out of your fans when the CPU is drawing the most current.

73, Hoot