Dell Precision M3800 Owner's Review

That's why I didn't consider those arguments but I am interested in the materials and he specifically wrote about what aluminum type was used in the MBP and how it was created etc. so I gave him more credit there.

 

Idk, he mentioned some type of fan type that MacBooks use that make them the quietest fans in the world. The thing is I can't find anything about those fans, and even if I'm wrong about that, the rMBP's fans are ridiculously loud. And given that he's wrong about that, then I wonder what else he's wrong about...

 

Even if free convection is a poor method of cooling, it still transfers heat and as such and you still get a warm notebook notebook chassis if it's metal. Look at it this way, you've got your CPU at 80 Celsius or more (under load), even if there is a thin layer of air, the inner part of the metal chassis will still be rather warm (my own guesstimate is 30 to 40 Celsius lower than the CPU temp) and the outer side of the chassis will be warm as a result. That's where the insulator properties come in, if the inner part of a slim aluminium piece is warm, the outer part will be warm too, aluminium is among the best heat conductors out there. If the chassis was in direct contact with the CPU, you'd have a chassis at a temperature almost equal to that of the CPU, instead, you get something that remains rather warm because the free convection drops the temperature by a fair amount, but still not close to room temperature.

Looking at reviews of the 2012 retina, the chassis can get as hot at 50 degrees Celsius on the outer part near the CPU/GPU, that is pretty warm on your lap. If you use a material like carbon fiber, the outer part of the chassis will be significantly cooler. Lower the thermal conductivity and assuming the heat flow is the same, you'll lower the temps by a good amount. By how much depends on the conductivity of the M3800's chassis. Aluminium has a thermal conductivity of ~240 W/mK, for the M3800's chassis, it will depend on the weave of carbon fiber and the polymer, so it's rather hard to evaluate, my heat transfer books put it at ~13 W/mK for graphite fibers, so I'd assume something similar for the carbon fiber of the M3800's chassis which will yield lower surface temperatures (note that they won't be lower by a factor of 10 though, you have to take into account the whole system when calculating the exterior temperature).

Your design choices are then:
Metal chassis which will give you a little bit better heat transfer, but higher surface temperatures.
Other material like carbon fiber which will give you lower surface temperatures, but at the expense of other things. Those could be lower structural resistance, style, etc.

There is no good or bad choice between carbon fiber or aluminium, the thing is that the extra heat dissipation not being a lot shouldn't be the main factor between choosing carbon fiber and aluminium.

The insulator is helpful, but it isn't necessary.

 

He's talking about asymmetric fan cooling which is not exclusive to Apple.

Thanks for the more detailed explanation tijo.

 

I should add though that at idle, a metal chassis might be enough to allow completely passive cooling, when the CPU is dissipating heat in the 5 W range without it getting too hot.

 

One thing aluminum has going for it is longevity. I wonder about the longevity of carbon-reinforced plastic over time with constant heating and cooling. In a couple of years the base could potentially be a lot more susceptible to cracking although I doubt it would be a huge problem for most people.

What material is used for the top of the M3800 around the keyboard and the touchpad?

 

The possibility is there, but that depends on what weave of carbon fiber they used as well as what resin, hardener and their manufacturing process. If done right, you won't have to worry about longevity under a cyclic temperature load.

 

Didn't drop out of the conversation. Just dropped out of the silly name calling. He is entitled to his opinions.

I decided to stick to the facts http://forums.macrumors.com/showpost.php?p=18236988&postcount=156

Too bad he was completely wrong about the type of aluminum Apple uses.

The IGZO panel is at least as good as the Retina display. I should have said that would only buy an M3800 or M4800 with the IGZO display. The double negative I used before was easy to misread.

Uncalibrated, the IGZO screen looks good. The white point is close to 6500k. The gamma curve is close to 2.2. Contrast is 800:1. Brightness is just over 400cd/l2. Calibrated, it is one of the most accurate panels I have seen in a notebook or on a desk.

The Retina panel on the MBP has excellent color accuracy. I have seen measured Delta E’s of 1.04 on the Samsung panel. I have seen Delta’s of 1.4 and 1.95 published as well.

The Sharp IGZO panel also has excellent color accuracy. The Delta E on the system I have is 1.0. As more XPS 15 and M3800 systems are reviewed, we will see how well panels measure across a variety of panels.

When calibrated, the measurements show the Retina and IGZO panels are effectively equals when it comes to color quality, contrast, and color gamut. The Samsung Retina panel might be better than the LG Retina panel, but you will know much more about that.

The IGZO panel is brighter and uses less power. It is probably why Apple is looking at putting IGZO screens into their 2014 iPads and MBPs. (http://www.extremetech.com/computing...-image-quality )

The IGZO screen also has a slight resolution advantage since it runs at 3200x1800. Having a touch panel is more of a personal preference than an advantage in my opinion, but you get it on the Dell.

Creative professionals may complain about the Retina and IGZO displays only covering sRGB, but none of them will complain about a calibrated Delta of 1. That is a big deal. The sRGB coverage is also better than many other notebooks.

 

That wouldn't surprise me since he was wrong about a lot of things.

 

Thanks again for the very detailed posts.

I had a minor question earlier too if you can find the answer easily. Does the k1100m always get used or does it switch to it only for more intense tasks. I'm guessing it's the latter but I just want to make sure. If it managed this battery life while always using the discrete GPU, it would be completely insane.