Cooling

One thing you'll have no doubt heard from all the pre-launch talk is that the GeForce FX's "FX Flow" cooling solution is rather large and rather loud. I'd kind of hoped that as with so many things these days the rumors were unjustified and that the fan was just on the ever-so-slightly noisier side of normal.... alas it's not!

The fan NVIDIA opted to use is Y.S.Tech BD5015 series blower with a rather impressive 7200RPM motor.

Unfortunately, all those revs add up to no more than 4.80CFM which by fan standards is rather dire and is less than the output from the dinky little 40mm unit ThermalTake ship with their less than stellar active memory cooling kit (5.1CFM). The advantage with this type of centrifugal fan though is that it has a much higher static pressure, not that it counts for much in this particular design of cooler.

For those of you unsure about it, static pressure in simple terms is the fan's ability to cope with obstacles, or "system impedance" such as perhaps narrow ducts or air filters, neither of which the FX has.

Speaking of air filters it's worth noting that the FX Flow's shroud is clear and in time this will draw in dust, grime and smoke that will no doubt leave it looking far from attractive. I've no idea why NVIDIA opted for clear unless it was inspired by the recent clear case trend but you can count on a little regular stripping and cleaning of the shroud, fan and sink for looks if you have a window or less often for efficiency when it gets gunked up.

	BD5015 SERIES
	50x50x15mm
	Airflow: 3.40 - 4.80 CFM Static Pressure: 12.10 - 23.70 mm-H2O Blade/Housing: Plastic UL 94-0 PBT Lead Wire: UL1007 #22 AWG Voltage Available: 12 VDC Function Available: N, A, I, F Bearing Available: 2-Ball Weight: 28 g

Much as I hate to admit it, those who rather cruelly referred to the FX as a "hair drier" probably weren't too far off the mark as it does have that same slightly annoying tone to it, though in its defense it's like a hair drier being used in the next room, not the same room. As a rough guide the infamous 6800RPM Delta Black Label 38CFM fan weighed in at the exact same noise level of 46.5 dbA!

The principle by which the FX cools is to gather the heat using a copper plate and then transfer that heat via heatpipes to a copper heatsink through which the fan blows cold air.

The idea behind a heatpipe is that a low boiling point liquid boils at the heated end of the circuit and travels along the pipe to the cooler end where it condenses and gives up its heat. It then returns back to the hot end either under gravity or by some kind of wick arrangement to repeat the cycle. This in theory is a very efficient form of heat management and is used in all kinds of things from laptops to air conditioning units.

My only concern here would be that so far as I'm aware, a heatpipe needs internal volume to operate and those pipes look just too flat to have any actual internal void. I could very well be wrong on either (or both) points but it doesn't look like the most efficient way to build a heatpipe. I'm also fairly confident that noise levels could have been taken down a bit with a little strategic baffle placement but maybe this was just a design decision too far for the already late FX.

For sanity's sake NVIDIA have incorporated what they call "silent running" which means the fan only actually kicks in when it needs to. It's activated both thermally as required and also fires up as soon as any kind of 3D data hits its pipelines. In some ways the firing up and spinning down of the fan is more noticeable than the actual running which you kind of get used to over time. I did notice while running the 3DMark03 optimised 42.68 Detonators that the fan would fire up even when a TV card was activated but fortunately switching to the 42.69 "shipping" drivers cured this problem. The 42.69s also kept the fan running for a period after the GPU had stopped receiving 3D data thus helping to keep it cool, something the 42.68s didn't.

A Closer Look

Installation/Drivers