MARK WILLIAMS TAKES A LOOK AT THE NEW PROCESSORS FROM
INTEL BUT FINISHES WITH AS MANY QUESTIONS AS ANSWERS
I ntel’s latest desktop CPUs,
codenamed Skylake-S, are fi nally
upon us. O cially known as Intel’s
6th generation of Core processors and
benefi ting from Broadwell’s previous, very
late, manufacturing node shrink down
to 14nm of Haswell, this 6th generation
focuses on bringing architectural
improvements aimed at increasing
performance through higher Instructions
Per Clock (IPC), not just the higher clocks
that a node shrink typically brings.
TOUCH, BUT DON’T LOOK
Unfortunately, despite having launched
two 6th gen CPUs already, Intel has been
very tight lipped about exactly what
they’ve done under the hood in Skylake
since Broadwell. There’s virtually no
information available on the topic. Intel
have instead chosen to withhold this
information until their Intel Developer
Forum (IDF) conference. Whether it’s
something ground breaking or they
simply wanted some fi ller content for the
conference, we simply won’t know in time
for this issue. So let’s talk about what we
do know.
The two CPU’s that have launched
in tandem with the matching Z170
motherboard chipset are the Core i7-
6700K and Core i5-6600K.
ENTHUSIASTS GET FIRST DIBS
Breaking from the tradition of the last few
generations which started with laptop
focused CPUs launching fi rst, these fi rst
two Skylake CPUs are entirely enthusiastfocused.
The i7-6700K can be viewed as a direct
replacement of the i7-4790K. It has four
hyper threaded CPU cores running at
a stock base clock of 4.0GHz that can
turbo up to 4.2GHz. That turbo is 200MHz
less than the 4790K, however the
architectural improvements since made
over the 4790K should help the 6700K
surpass it in most cases.
The i5-6600K e— ectively replaces the
i5-4690K. It too has four CPU cores but
like most i5 class processors it is missing
hyper threading. It operates at a base
clock speed of 3.5GHz with a turbo clock
of 3.9GHz.
THE PLOT THICKENS
Both are somewhat surprisingly rated at
a 91W TDP, which is higher than the 84W
of Haswell processors of two generations
ago on the larger 22nm process node.
While Intel is keeping its cards close to its
chest for now on the nitty gritty of these
new Skylake chips, the fact that the i7-
5775C (Broadwell-DT) managed to shrink
Haswell to 14nm, more than double the
IGP size AND add 128MB of eDRAM yet
still only draw 65W, shows that there is
potentially a much higher transistor count
in Skylake CPUs than what we might
currently think.
To add further to the mystery, several
things have been removed from Skylake
since Broadwell.
Such as the
audio subsystem
which has now
been completely
shifted o— to the
Z170 chipset; the
Flexible Display
Interface (FDI); the
fully integrated
voltage regulators
(FIVR) has also
been moved o—
package to the
motherboard;
the introduction of DDR3L/DDR4 which
operates at lower power envelopes; and
the complete absence of eDRAM on
these new processors over Broadwell-DT.
It does make you wonder where all this
extra 26W in power over Broadwell-DT
is disappearing to because the initial
performance results don’t show any
abnormally large gains
AN ACE UP THE SLEEVE
On the iGPU side of things both the
6700K and 6600K have a HD Graphics
530 (GT2) branded processor on board,
which appears to be essentially the same
as that of the HD Graphics 4600 (GT2)
found in its Haswell Refresh progenitors.
The only di— erences being that the
maximum IGP frequency is now 50-
100MHz lower at 1.15GHz but with an extra
four Execution Units (EUs) on-board for
24 total over the previous 20 EUs leading
to measurable increases in integrated
graphics performance.
VGA connections are now no longer
supported out of the box (although
can be added with an active digital/
analogue converter chip by motherboard
makers). Interestingly it appears all of
the 9th generation IGPs house an empty
controller for an optional 64MB or 128MB
of eDRAM (L4 cache). With the success of
Broadwell-DT’s eDRAM in boosting GPU
performance, fi nally giving Intel the lead
in the iGPU stakes versus AMDs o— erings,
it appears Intel has built in the option to
add eDRAM into future CPUs to give them
a decisive reply against anything AMD
brings out in the short to medium term to
press home Intel’s advantage before AMD
likely bring in new HBM-equipped Zen
based APUs.
On a fi nal note, both the i7-6700K and
i5-6600K CPUs, in a fi rst for Intel, do
not ship with a heatsink fan cooler in the
box. Being enthusiast-grade products
with unlocked multipliers, the reasoning
behind the omission is that buyers would
likely be using 3rd party coolers anyway.
And yes, your current 1150 socket cooler
will work just fi ne with these new 1151
socketed CPUs
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