xp-90 fanless with 25-watt sempron?

dan · Post by **dan** » Mon May 09, 2005 7:16 pm

Hello,
i've been thinking of buying an xp-90 from www.bestbyteinc.com. I bought a seasonic tornado 300watt, thanks to SPCR, and a soltek SL-K8AN2E-GR, which allows me to undervolt from default to 1.05 volts, about a 50% reduction from default. Sisandra reports or estimates power consumption at 25 watts. I am using a retail heatsink and fan, with the fan volted at 5 volts, also learned from SPCR (the 4-pin molex is on backwards).

The soltek hardware monitoring utility reports CPU temp at 25 C.

The soltek does NOT allow me to control fanspeed. i'm using a matrox g450 card. neither cpu or gpu is overclocked.

with the tornado as the only fan, would it be a good idea to buy an thermalright xp-90 and run my setup fanless?

wsc · Post by **wsc** » Tue May 10, 2005 2:43 pm

Try it, it may run 100% stable but I'd be suprised. As long as your system will shut off or throttle down if the temp gets too high you'll be okay. You may discover that you have to underclock so far to reach fanless stable operation that it's just not worth it, but you may not...

dan · Post by **dan** » Tue May 10, 2005 7:57 pm

well the reason i ask is that i'd like to have fanless but rma'ing is hassle, and i am right at the borderline, i say that b/c with stock heatsink/fan at 5v, the cpu temps are around 26C.

so i figure xp-90 maybe i can go fanless? if i need a fan for an xp-90, then i might as well rma it and stick with the retail hs/fan

Natronomonas · Post by **Natronomonas** » Tue May 10, 2005 8:40 pm

If temps are at 26C now, I would guess that you could run the XP-90 fanless provided you had some case airflow moving past it (exhaust fan nearby or something).

However, I think it's something you're just going to have to try, unless you've got a friend who'll loan you for a while.

Out of interest, what temps does it get to on stock h/s without the fan??
That's probably your best guide - XP90 is about ~.2C/W, while stock is going to be about double that, so .4C/W, WITH fan.

So, assuming that correlates to fanless performance, you should see about half the rise in temp over ambient than you do with the stock h/s.
However, this is all theoretical, so I'd be guessing you'd see an improvement with the XP90, but not double.

metalac · Post by **metalac** » Wed May 11, 2005 5:07 am

please try it

. I want to see the results too. I'd try it but I don't have an XP-90 on me right now.

Here is what I would do:

- Crank down the voltage as far as you can go and then lower the frequency to say 800mhz or whatever is the lowest. I had a CPU this way at 23C with 23C enviroment

.

- Slowly start increasing the frequency, by say 100mhz and bump up the voltage as needed. This way you'll know if it's possible, if it's say 50C when you are at 1200mhz and nowhere near the actuall speeds, then it's probably impossible to do, but if you make it to about 1800mhz with 50C it might just be possible.

- Also I would turn off that case fan, so this way you get "pure" heatsink performance and see how it goes, since if it does ok without a fan it can only get better with that case fan, but the question again is how much better.

Anyways good luck, and hopefully nothing will go wrong.

dan · Post by **dan** » Wed May 11, 2005 9:29 am

one problem though is that it appears that SL-K8AN2E-GR SOLTEK allows for undervolting (correctly listed in the undervolter's section) it apparently doesn't allow for front side bus underclocking (though it does allow the memory to run at a slower speed). it does allow for overclocking, which isn't helpful in my case.

the only ventig i have is the seasonic tornado 120mm fan, which as far as i can tell is inaudible.

even at 5 volts i can hear the stock retail fan. i'm using the soltek hardware monitor, and i believe it is accurate. when i touch the heatsink with the fan at 5v, it is very cool to touch. when i disconnect the fan, i'd say over an hour, the soltek monitor reports temps as high as 50C, and when i touch the heatsink, it is blisteringly hot.

metalac · Post by **metalac** » Wed May 11, 2005 9:40 am

Well I have Abit NF7-S v2.0 which allows for undervolting down to 1.1V and lowering both the multiplier and FSB, so maybe I should give it a shot. Only problem with me is that I have some POS heatsink that I picked up somewhere for $5 and even though it's better than the stock it's no XP-90. I guess I should get me a quality heatsink and see how it goes. I have 2400 Mobile in this box and this is not it's final resting place. It was mean for my HTPC box, that due to school work and job was on hold. Once the summer comes I should be able to get it finished and start some real testing. I'm hoping to go FULL ON FANLESS. I'm willing to downgrade the processor down to 1.2ghz. It looks like it's quite possible, since at those frequencies it only puts out something like 17W or so.

Bitter Jitter · Post by **Bitter Jitter** » Wed May 11, 2005 10:44 am

dan wrote:The soltek does NOT allow me to control fanspeed.

Does that mean that you have tried SpeedFan?
I did see that Soltek have an Nforce 250 chipset board on there, although i doesn't look like your one.

Also have you thought about a 70mm - 80mm fan adaptor and very slow fan?
Was that 50c measurement at idle or after load?

dan · Post by **dan** » Wed May 11, 2005 6:24 pm

yes i did try speed fan. it worked on my older, retired soyo TISU, but it doesn't work on the soltek, which soltek's tech support verified.

yes it's a nvidia 3 250g chipset. i think it's the ITU chip that determines fan control, not the southbridge.