Possible to Underclock a Asus A8v, BUT by bios only?


I have a new PC at home, so i have turned my previous PC into a NAS Server using "Naslite" software, which is all good.

However as the basic specs for a naslite box is 386 pc or above and my unit is 64bit 3000+ AMD on a Asus A8V MB i am really having too much power speed, the problem i have is that i want to run server 24/7 at home but currently the CPU etc is too noisy with fan cooling running as the processor is warming up even without load.

What i wanted to do if possible is to Underclock the CPU (and or MB if needed) and therefore slow the cpu down and hopefully slow the fan etc and noise down. I can only of course use the MB bios to achieve this, as there is no OS running as such on unit, so cool'n'quiet etc isnt an option.

The Asus bios has all the included settings for clocking and has manula settings for FSB/Voltages/Mutlipliers but to be honest i am unsure which settings to maybe change or lower to try slow the CPU and hopefully cool/quiet the tower down.

REally hope someone can help
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MadAd1Connect With a Mentor Commented:
A8V & 3000+

well the the board has settings down to 4x and 0.8v vcore and bearing in mind we are talking 'out of spec' performance here so YMMV, on the newer amd boards CnQ defaults as low as 40% of the normal multiplier so id treat half normal as your base and go from there.

It depends on which 3000+ you have, a normal multiplier is between 9x  and 13x for those so youll have to look at yours and work it what half is.  And obviously if you can find a satisfactory medium somewhere above middle then all the better too.

Vcore similarly can be reduced, again depending on what 3000 you have, if its default voltage is 1.5 or over then 1.25v as a minimum, but if your default voltage is 1.4 or lower, then treat 1.1v as your floor.

AMD CPU list http://www.thedigerati.us/info/amdcpuchart.html#64x2  <<so you can look yours up

I would always recommend testing with at least memtest before deciding on a low setting, ideally prime95 but I understand that is not possible with your NAS s/w- could you not run a test install of xp/9x to test multiplier and Vfloor then once found, install the NAS?

However by far a cheap and easy way to shut down pc fan noise is to instal large 120MM fans but run them near 7v (via a fanmate -zalman-cheap) making them virtually inaudible yet still producing CFM figures that the little buzzy fans do on maximum.  I have 5x 120mm in mine running between 34 and 40% and the loudest part I can hear is the videocard cooler and the occasional disk clicks.  Look at the:

Thermalright si-120 http://www.thermalright.com/a_page/main_product_si120.htm

plus there are several others that take 120mm fans, and with one on the CPU, one on the case and a decent PSU with a 120mm fan in your noise problems would be shifted to the next noisy component (probably drives). Fortunately you have no chipset fan on that board.

Lastly a couple of links, heres a nice AMD forum for hardware clocking tools and tips http://www.xtremesystems.org/forums/forumdisplay.php?f=58
Silent PC, search for things like undervolting, its common here

good luck
To underclock, do the reverse of overclock: lower the FSB from the stock setting of 200.  You may also be successful at lowering the voltage of the cpu and RAM, but this requires more testing.  You could also get a Zalman 9500 cpu cooler, as it is one of the most efficient cpu coolers and runs very quietly.  There are also a number of water cooling units available.
LeeBennettAuthor Commented:
Ok just tacken a look at bios, seems the fsb cant be lowered :-( it has options for higher settings but nothing lower than 200. There are options to lower voltage and multiplier still and laso some settings to change "hypertransport" settings? Will lowering some of these without changing FSB slow CPU down?

Yes i may get a silent cpu cooler, but really was trying to avoid any new parts or costs, purely because if i spend cash i may as well lower system by buying an pentuim etc.
If you can't lower the FSB, try decreasing the multiplier.  You want to lower the overall cpu speed, which is the product of the FSB and the multiplier.
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