Why is the new MacBook Air not "a bigger MacBook"?

Let's start with what is a "Y" processor and what it is not.

Intel's ultra-low-power chips previously called "Atom" and had a completely different architecture than processors for desktops and laptops. It did not go well for a variety of reasons, so Intel dropped Atom. To replace it, Intel has borrowed essentially the chips of the series "U" which knew a resounding success on MacBook Air and Windows Ultrabooks, slowed down and reduced, and created a new category of processors. They are designed to consume less energy than the U series chips, or rather to produce less heat. Intel achieves this by limiting power consumption.

A small note: according to the chip, Intel refers to these processors as Core M or simply launches a Y somewhere in its model number. C & # 39; exasperating. Previously, they all called Core M, so I'll call them Core M for simplicity.

The chips of the entry-level MacBook trio are quite similar. All have the same basic processor architecture, with equal number of cores / threads (2 and 4 respectively) and cache size. They diverge slightly in function and the U series chip in the dual-core MacBook Pro combines with faster RAM and less power, but the main differences are clock speeds and integrated graphics.

The 12-inch MacBook comes with a m3-7Y32 in its basic configuration at $ 1,299, or an i5-7Y54 chip at $ 1,399. Despite the prefixes "m3" and "i5", it is essentially the same chip, set differently. Intel lists them even at the same suggested price on its website. The m3 has a base frequency of 1.1 GHz and a maximum turbo frequency of 3 GHz, the i5 has a base frequency of 1.2 GHz and a maximum turbo frequency of 3.2 GHz. Although I do not have two machines in front of me to test this theory, the i5 will probably increase the clock speed more aggressively, but beyond that, they are very similar.

The new $ 1,199 MacBook Air has not been dissected yet, but it certainly contains the i5-8210Y. Also a Core M, it has a base frequency of 1.6 GHz and a maximum turbo frequency of 3.6 GHz. That seems to be a variant of the 8200Y that we saw in convertibles like the Dell XPS 13 2 in 1. Where the air differs from both the MacBook and the XPS, it's its cooling: it seems to have a fan, which would make it a much more efficient machine. In fact, in terms of performance, it is close to the third laptop in the Apple range.

The MacBook Air fan made a brief appearance on stage yesterday.

This laptop is the entry-level MacBook Pro. The $ 1,299 version has an i5-7360U, which has the same 3.6 GHz turbo frequency as the new Air, but runs at a base frequency of 2.3 GHz. It also has Iris Plus Graphics 640, while all the chips I've mentioned so far have had UHD Graphics. Without going into too much detail, the UHD graphics are only meant to ensure smooth operations, such as video decoding, while Iris Plus Graphics assists you in configuring multiple monitors and even lets you play something light, like Dota 2 on the low settings.

Thus, on paper, all processors are two-core processors capable of reaching speeds between 3 GHz and 3.6 GHz. But in reality, the three implementations are quite different. Intel offers a useful but often misunderstood measure to help us understand why: Thermal Design Power (TDP). Rather than measuring the power of a processor, TDP tells us how much heat it dissipates at a certain frequency.

All Core M chips are designed for almost identical TDPs at the same frequency. At idle at 600 MHz, they will probably dissipate about 3.5 W of heat, at 1.1-1.3 GHz, they will reach 4.5 W and 1.6 GHz, they will all be around 7W. Unfortunately, Intel does not publish more than the Core M TDP figures, but the dual-core MacBook Pro series dissipates 15W at 2.3 GHz and, given the architectural similarities, the Core M chips are probably in the same approximation .

TDP is primarily useful for the manufacturers Intel sells: It helps them choose the right part for their device. Apple, for example, knows that if it launches a chip that dissipates 7 W of heat in a chassis capable of dissipating 7 W of heat, it does not need a fan and that's what it did with the MacBook 12 inches.

Nowadays, everyday computing throws a few curved balls – times when you need more power to prevent a machine from stalling – and that's why there are boost clocks. They allow a chip to reach higher speeds as long as it can stay cool before reducing the frequency. A desktop PC with a good cooler can endure indefinitely a high-acceleration clock. Apart from gaming laptops with giant vents, wearable machines usually can not. It all depends on the cooling system put in place by the manufacturer.

However, when a system does not have a fan, there is a fixed limit for heat dissipation. For this reason, the 12-inch MacBook, for example, is not able to switch to the advertised top speed in daily operations. The lack of fan also means that room temperature plays an important role in performance. As I discovered in March at SXSW, working in the warmth of the Texan sun can seriously degrade performance. Indeed, unless you do literally nothing, the processor of the MacBook i5 will not be at its base clock at 1.2 GHz: it is almost always hovering above 1.5 GHz during its normal running.