Low Voltage Athlon

[k900]

Hey guys, I have an old Asus A7V motherboard with an athlon 1 ghz (100 mhz bus) that I want to turn into a dedicated media computer. This motherboard can accept any socket athlons with a 100 mhz bus. I am looking for something really really quiet. Is it possible to put a laptop processor in there or can I underclock my 1 ghz processor if I'm just going to be using this as a PVR(personal video recorder- like tivo).

Any input would be greatly appreciated, or any other advice you may have on a quiet system.

Thanks,
Kevin

 

[Jeff7181]

A lot of people take an XP1700 and underclock it... running it with a 100 Mhz bus with a 7.5 multiplier will give you 750 Mhz, more than enough for a media PC... and that's half it's rated clock speed, so it will run cooler because of that, and that will also allow you to reduce the voltage, which will let it run cooler yet. I'd be interested to hear if anybody has a passively cooled Athlon XP in a media PC. As long as they stay under 70 degrees C, they should be fine. (I know they're rated for 85, but I say 70 because you never know how high or how low your motherboard is actually reading the temperature.)

 

[k900]

would that run in my Asus A7V motherboard at 100 mhz bus?

 

[Jeff7181]

Hmmmmm... although I don't think Athlon XP's are officially supported... it MIGHT work. An old AnandTech review of it says voltage is adjustable from 1.3 volts to 1.850 volts. So I bet you could stick an Athlon XP 1700 in there, and it would use a 100 Mhz bus, which would give you 1100 Mhz... it says it supports down to a 90 Mhz bus, so you could set it at that, and get 990 Mhz, and it might run at that speed at 1.3 volts. However... it would probably be easier to get a newer motherboard that supports Athlon XP's and will allow you to adjust the multiplier.

Either that, or stick a massive heatsink on your 1 Ghz Athlon, set the voltage as low as you can get it stable, and use a large, but low speed fan on the CPU, and have a couple large, low speed fans to move air through the case.

An alternative would be a heatpipe setup similar to what's used in those Shuttle mini PC's. I believe they use 1 fan for the whole PC, and they have XP1700's running at their default speeds.

 

[ChampionAtTufshop]

update to latest bios and it will work
ive done it
my xp1700+ ran at default mhz at 1.3v no problem
my 1ghz tbird ran at 1ghz at 1.4v no problem

to passively cool either i dont think it would work...
maybe on the xp1700+ if you underlcock to 7.5x100
but you might as well try it on the 1ghz tbird first
underclock it and see how it fares

 

[k900]

how did your xp 1700+ run at default mhz since the motherboard doesn't support a 133 mhz bus?

 

[GoHAnSoN]

look at my rig
Tbred 1700+ from new egg will go 20x100 no problem after cutting the rightmost L3 bridge(default voltage).
i bet you can run it at 11x100 fine and cool.(without touching anything to the cpu)

but u need to update your mobo bios to the latest ones.

EDIT: what u need to do now is simply buy one 1700+ from newegg.(or anywhere), update bios , and plug the cpu in with everything set to jumperless. i'm sure you will run at 11 x 100 and pretty cool.

 

[ChampionAtTufshop]

Originally posted by: k900
how did your xp 1700+ run at default mhz since the motherboard doesn't support a 133 mhz bus?

to run at default speed i needed to chop 3 bridges on the cpu
the 3 rightmost L3 bridges
that defaulted the mult to 17x (note, i already knew the cpu would do 1700mhz at default voltage, thats why otherwise i would have gone for 15x, which is cutting the last 2 bridges i believe)

note that all of the higher mults are remapped when you cut the last L3 bridge

 

[GoHAnSoN]

no. u only need to chop the rightmost L3 bridge.
the other 4 can be set via your jumpers.

PS: i'm doing on a Tbred "B" only. Tbread "A" have different multiplier.

 

[ChampionAtTufshop]

Originally posted by: GoHAnSoN
no. u only need to chop the rightmost L3 bridge.
the other 4 can be set via your jumpers.

PS: i'm doing on a Tbred "B" only. Tbread "A" have different multiplier.

thats waht i meant, if you cut the last L3 bridge (right most), you can change all mults via dip switches but they are all just remapped
i was gonna go through that process, but i found someone wiht the same mobo who went ahead and did that already so i just used a mult of 17 x 100mhz cuz i knew it would work at 1700mhz no prob