Is Intel’s Core M efficient
Updated(27-12-2014)
At IFA 2014, Intel gave us the
full skinny on its fifth-generation Broadwell-based Intel Core M CPUs. The
chips would be thinner, and more energy-efficient than past CPUs, while also
offering solid performance. They would pave the way for slimmer, lighter devices
than anything we’ve ever seen before.
If our time with the Core
M-powered Lenovo Yoga 3 Pro is any indication, that latter bit is true.
But what about the energy efficiency and performance aspects? Does Core M
measure up, or does it come up short?
What’s
Core M supposed to do again?
The most efficient chips from
about four years ago need 18.5 watts to operate. Similar chips from last year
require 11.5 watts of power. Core M cuts that number down drastically, asking
for a mere 4.5 watts of juice.
However, there’s more to Core M
than increased efficiency, and (presumably) better battery life for whatever
devices it’s in. Core M chips are also, as we mentioned, much smaller than
their older siblings. Core M hardware measures 30 x 16.5 x 1.05
millimeters thick, while fourth-generation Intel hardware measures 40 x 24 x
1.5 millimeters. That’s a significant reduction
Related: Intel dishes on Core M at IFA
2014
So, it’s simple math. Smaller
hardware means more space in system cases for PC makers to work with. This, in
turn, leads to slimmer, and lighter devices, like in the case of the Yoga 3
Pro.
Also, because Core M sips on
energy, it can operate while fan-less. This allows computer manufacturers to
omit components from their systems that are associated with keeping internals
cool, including fans, heat-sinks, and air vents.
Sizing
up our Core M chip
Keep in mind that Core M
consists of a family of chips, not just one part. The one we got our hands on,
the 5Y70, is the second most powerful Core M chip that Intel is launching as
part of this wave of silicon. The Intel Core M-5Y70 is a dual-core chip clocked
at 1.1GHz, with a Turbo Boost clock of 2.6GHz.
Not only is this the fastest
Core M chip that’s out now, it’ll only be 100MHz slower than the highest-end
Core M chip that Intel is launching this year. The next chip up on the totem
pole is the 5Y71. That CPU runs at 1.2GHz, sports a Turbo Boost clock of
2.9GHz, and is also a dual-core chip.
Graphics performance
Processing power may not be the
CPU’s forte, but how does the Core M’s Intel HD Graphics 5300 GPU get by?
The Lenovo Yoga 2 Pro scored
3,889 in 3DMark Cloud Gate, and 579 in 3DMark Fire Strike. The Dell XPS 13 got
4,507 and 627 in the same tests, respectively. The Lenovo Yoga 3 Pro lags
behind both significantly, with scores of 2,636 in Cloud Gate, and 376 in Fire
Strike.
Though the Yoga 2 Pro and the
Dell XPS 13 don’t conquer these tests, they’re in a different league. Both have
well over 1,000 points on the Yoga 3 Pro in 3DMark Cloud Gate, and scores that
are at least 200 points higher in Fire Strike.
Combine that with real-world
performance, and you’ve got yourself a clear picture of what a graphics chip
can do. We fired up League of Legends, a popular game that’s also the least
demanding title we use to test GPUs.
Forget about enjoying it with
the Core M, at least on the Yoga 3 Pro. With League of Legends running at the
display’s native resolution of 3,200 x 1,800, the game ran between 18, and 8
frames per second. The game’s visual details were set to Medium.
For what it’s worth, we’re
curious to see how Core M will fare on 720p and 1080p systems. We think it
could manage at 1080p based on its 3DMark score, if only by the skin of
its teeth.
Better endurance
In the Peacekeeper Web browsing
benchmark test, the Lenovo Yoga 3 Pro lasted only three hours and 44 minutes on
a single charge. That’s a notable improvement of 30 minutes over the Yoga 2
Pro’s time of three hours and 14 minutes. Both notebooks have 3,200 x 1,800
displays.
The Dell XPS 13 is in another
league here, lasting seven hours and 48 minutes in the same test. Of course the
13 has a much less demanding 1080p display to work with.
Since both Yogas are forced to
push an extremely high amount of pixels, the battery is taxed significantly as
a result.
These days, 1080p is the sweet
spot of display resolutions. That’s especially the case with laptops, where
battery life has to be a key consideration when PC makers outfit their systems.
As with graphics capabilities,
we want to see what Core M can provide in a 720p or 1080p system. In the Yoga 3
Pro, however, no amount of CPU-centric power efficiency can save Lenovo’s
latest from a poor battery life score.
Better
than it seems
The
Intel Core M looks like a disappointment. It’s not as quick as previous Intel
4th-generation processors, and it doesn’t always lead to outstanding battery life. You might
be wondering – what’s the point?
Closer inspection, however,
reveals there’s actually significant improvement here. Consider
the multi-core GeekBench score of 4,267. That’s several hundred less than
the an ultrabook with an Intel Core i5-4200U, but that 4th-generation
processor has a quoted Thermal Design Power (TDP) of 15 watts. The Core
M-5Y70 has a quoted TDP of 4.5 watts. On paper that means the Core M manages
almost equivalent performance on a third of the power. In reality TDP does not
translate to actual power draw (it’s a guideline for laptop manufacturers, not
a benchmark), but in any case it’s clear the Core M consumes far less juice.
That may be hard to believe
given the Yoga 3 Pro’s poor battery life, but several of Lenovo’s design
decisions make life difficult even for the Core M. The most important is
not the screen but rather the battery, which is rated at 44 watt-hours. That’s
not small, but it’s not large, and it’s ten watt-hours smaller than the battery
in the Lenovo Yoga 2 Pro. In other words, Lenovo’s design choice to save weight
by reducing the size of the battery has mostly negated the advantage of the
new, power-sipping processor. Most manufacturers will not make the same
decision.
And
remember, this early look at Core M and Broadwell is just the first slice of
the pie. CES 2015 is where Intel will reveal the meat of its product line, and
while the official details of those chips aren’t yet available it’s safe
to assume we’ll see some with a 15 watt TDP (or somewhere near), just as with
the 4th-generation Core line. Those processors will likely manage a noticeable boost
in both battery life and performance. 2015 may prove an excellent
time to upgrade if you own a laptop that’s getting on in years.
