EVGA 680i LT SLI: NVIDIA's 680i Cost Reduced

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• Stele - Wednesday, March 28, 2007 - link

  quote:
  

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  Also, Jarred, or whomever else would like to answer, how hot does the PWM section of this motherboard run ? Seems lately, dual core on up motherboards tend to run hot in the PWM.

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  It boils down to the engineering headroom put into the PWM design. Let's say the maximum supply current anticipated from a generation of CPUs is 50A (usually from datasheets and/or design guidelines from the CPU manufacturer). Motherboard designers can design their PWM to be just sufficient for this - most notably, the MOSFETs chosen may be those that can handle around 75A - or they can build some headroom in and choose MOSFETs capable of, say, 100A.
  
  The former design philosophy saves cost, and after all it gets the job done. However, since the components would be running near their design limit, they would generate quite a bit of heat... especially during spikes of load and/or when new CPUs with even higher current draw (e.g. quad-core CPUs) show up.
  
  The latter design philosophy is more expensive, but because the components would be running well below their rated spec, they fare much better in terms of thermal dissipation (and hence efficiency, as less power is lost as heat). The lower running temperatures also help improve the reliability of the components since less thermal stresses are present. Furthermore, when current loads increase - be it due to sudden load spikes and/or power-hungry CPUs and/or overclocking - they still have a lot of headroom, and so are able to handle the extra load without breaking a sweat. This results in better stability and again, lower heat dissipation compared to lower-spec'ed components at the same load.
  
  In view of this, perhaps one other area that Anandtech could look at when reviewing motherboards is to have an IR thermometer handy (the ones that you can point and measure temperatures of surfaces remotely with) and perhaps measure the temperatures of the chipset and PWM (or at least the temperatures of their heatsinks) at idle and load. It may not be perfect (especially when heatpiped, and a hotter heatsink could also mean that the heat flow from the component to the heatsink is good due to good thermal contact) but imho at least it would give a useful ballpark figure.

• Stele - Wednesday, March 28, 2007 - link

  Pretty good review, critically assessing the chipset in light of theory (paper specs) as well as reality (actual value for money based on real-world prices and competiting products).
  
  IMHO, Nvidia's attempt to create a lower-cost version of the 680i SLI by limiting BIOS options and tossing the odd feature out (like passive chipset cooling and two USB/one network port) seems a little clumsy at best... Instead, I think the hybrid chipset combination used in, for example, the Asus P5N32-E SLI Plus is a more elegant solution. As this review demonstrated, the BIOS options do not necessarily cap the LT's overclocking capability enough to prevent it from being a threat to the 680i SLI's exclusive turf. Indeed, it might well turn out that the latter's sales would not be jeopardised by the LT anyway - not because of the arbitrarily imposed limitations, but because of the almost non-existent price difference between boards based on the two chipsets, considering the lost features.
  
  Meanwhile, other reviews of the P5N32-E SLI Plus have noted that the MCP used is that from the AMD-platform 590 SLI chipset. I wonder if, other than the slight rearrangement of PCI-Express lanes, there are any real differences (e.g. revised/improved networking/disk controller engines etc) between the two MCPs? Or are these blocks nothing more than carried over directly from the 590 SLI? It would be great if Anandtech could look into that.
  
  Lastly, a tiny note - it's a little amusing to note how it must be a bit pedantic to have to spell out the full name of the 'solid' capacitors used... at least Anandtech strives hard to get it right! :) Really, though, for the kind of 'solid' capacitors that we're talking about on most motherboards, "aluminium solid electrolytic capacitors" or even just "solid electrolytic capactitors" (vs. 'regular' (liquid) electrolytic) would do perfectly. Conductive polymer capacitors are generally (though not restricted to) the little rectangular ones such as the ones seen on Asus RoG boards as well as the P5N32-E SLI Plus. Just a thought :)

• yyrkoon - Wednesday, March 28, 2007 - link

  Well, about the capacitors, I know as per some OEM, anandtech was calling them 'solid state capacitors', which you sound like you know enough about electronics to know this is wrong. Anyhow, several readers, including myself called 'foul', and there you have it . . .

• JarredWalton - Wednesday, March 28, 2007 - link

  There were a few complaints when he used "solid capacitors", so I guess the full name is the safe way to go. LOL

• Stele - Wednesday, March 28, 2007 - link

  Oh very true! "Solid capacitors" and "solid state capacitors" (as yyrkoon rightly commented) are both commonly used on many hardware sites, and are both inaccurate. One reason for the repeated complaints, iirc, is that we were simply oscillating between one inaccurate term and another. :P
  
  "Solid electrolytic capacitors"... now that is perfectly acceptable, despite a difference of one word. The devil, as they say, is in the details. ;)

• yyrkoon - Wednesday, March 28, 2007 - link

  You did the right thing Jarred, you know how picky 'us' readers are ;)