by ianthompson » Tue Nov 30, 2004 8:41 am
Oops, sorry - I wasn't challenging your review, just putting forward some personal observations for the possible benefit of others.
Perhaps more info will help?
1. Yes, & herein lies the problem of 'non-integration' for certain applications.
2. Again, I agree - but I'd prefer to know about a problem BEFORE all hell breaks loose (e.g. engine temp guage, vs idiot light!). I just happen to think the design approach taken is weak.
3. Perhaps the following will give you a better clue as to how it all seems to happen.
Firstly, I'm using a Prescott P4 that apparently dissipates 103 W at full chat, and a Zalman cooler that's rated at 0.22 deg C per W. So when running a heavy application (NASA's World Wind, for example), the case fan is kicked up to full power pretty quickly. There are a number of technical issues (die/heatsink conductivity, heatsink thermal inertia, etc.) I could go into here, but will leave for another time. Simply, a thermal wind up commences.
My case fan can 'suck' at perhaps 0.25" W.G. at full chat, but at this time the PSU is still happily chugging along at only 850 rpm, since it's internal temps haven't changed much. It's not hard to see how the PSU fan blades could be easily 'stalled' (aerodynamically) with such a back suction over them at such low speed. Also, I have temporarily fitted precision temperature sensors at the PSU outlet, and inlet. The "in" temp is 8 deg C higher than the "out" temp, ergo - backflow! And so the PSU is cooled (backwards) and has no reason to ramp up it's fan.
I tried the suggestion of simply using the PSU fan drive outputs, but this didn't work for me as the board ambient limits were exceeded (Intel want a max. of 38 deg C ambient, probably for the voltage regulator capacitors). My solution works MUCH, MUCH better.
4. Yes, well, I design these sorts of things for my job. Perhaps you should understand the internal fan's tacho and negative line ARE ALREADY connected to the outside world (the monitor socket), so all I had to do was lift the fan positive line and bring this out as well alongside the others.
And yes, perhaps I was being a little harsh on Antec - they did respond quickly to my initial enquiry - probably missing the point - but could not then provide details of the fan drive (proprietary). I was hoping to tweak the fan drive gain/offset to get the fan to ramp up earlier.
My overall objective - to minimise noise. Both the PSU fan and case fan start to become intrusive at around 1300 rpm (other reviewers have commented on this), but at this speed the case fan is shifting HEAPS MORE AIR through the Sonata. And with ALL fans at full wack the internal ambient is STILL MARGINAL when doing heavy processing - this at an office ambient of 24 deg C. What am I going to do this summer, when 30 deg is not uncommon - fit an aircon?