Intel and AMD have long battled to
empty consumers' wallets by offering the fastest processors. With this new
selection on the market, the choice is harder than ever. We put 62 top chips on
test to find out which is most worthy of your cash.
Intel
vs AMD
Upgrading your PC with a new processor
isn’t always a case of just ordering one and locking it into your motherboard.
There are important factors to take into account, and they become more numerous
as your PC gets older.
The main consideration is the motherboard.
Every generation or so, a new range of processors will make a move to a new
socket, designed to take full advantage of their capabilities. This means you
can’t usually put a new processor in a motherboard that’s more than two years
old and expect it to fit.
The feature table opposite shows that the
current generation of CPUs is based on only a handful of sockets, so it isn’t
as complicated as it has been in the past; however, it pays to be sure you have
a compatible motherboard before making a purchase.
The second consideration is graphics. The
majority of processors available today include an integrated GPU, so as long as
your motherboard has video outputs, you won’t need a discrete graphics card as
well. Some boards - mostly at the low end - don’t, however; so again be sure to
check the feature table before buying, otherwise you could find yourself
needing to shell out for a card just to get your monitor connected.
The final consideration is cooling,
although you could simply use the cooler that’s included with your processor.
This will be fine in normal use with many of the latest processors, and it’s
also fine for mild overclocking - most have plenty of headroom. If you want to
perform serious overclocking, however, it can pay to invest in a proper
third-party cooler, as temperatures can become pretty toasty as you push up the
frequency ever higher.
The latest Ivy Bridge Core i7 chips
approached 100°C when we ran stress tests with the stock cooler. Overclocked
systems regularly arrive in the Labs, and these clearly demonstrate the extra
heat generated: Core i5 and Core i7 chips running at 4.6GHz and upwards push
even the best third-party coolers to their limits.
If you’ve thought about all of these
aspects and know what you’re after, turn the page and start reading our
breakdown of each processor family. Then flip to pi58 to see where they sit in
the price-performance graph. There’s a perfect chip for all budgets.
How we test
Performance is divided into three
categories. The Media test uses Adobe Photoshop CS5, Sony Vegas Pro 10 and
Apple iTunes to edit and encode images, audio and video into a variety of
formats. The Multitasking test runs a selection of applications designed to
evaluate the multicore and multithreaded processors in this month’s test. The
third test - Responsiveness - opens, moves and closes multiple applications and
windows to simulate everyday Windows usage; the better the score, the livelier
your system will feel.
in
a real-world test using Adobe Photoshop CS5, Ivy Bridge was once again the
fastest chip tested but the margin of victory was much smaller – only two
seconds faster than its counterpart
We also load up our Crysis, Just Cause 2
and DiRT 3 benchmarks at a variety of resolutions and quality settings to test
the gaming potential of the various graphics cores included in both Intel and
AMD processors. Our thermal tests evaluate the idle and peak temperature of
each processor, and the power requirements of our test rig with different chips
installed.
Value for Money
The Value for Money score is based on the
benchmark results of each chip - we take this data, factor in how much each processor
costs, and deliver a bang-per-buck result. We’ve combined much of this data
below, so you can see exactly which processors represent the best and worst
value for money.
Overall
The Overall rating is an average of the
Performance and Value for Money scores, although due to rounding the figure may
be higher or lower than you’d expect.
Test rigs
This month has seen several different test
rigs built in the PC Pro labs, with LGA 1155, LGA 2011, Socket FM1 and
Socket FM3 machines assembled in order to test all the processors on the
market. We standardised equipment as much as possible across all of our test
systems: each uses 8GB of DDR3 RAM, a top-end SSD for storage, and a discrete
AMD Radeon HD 6500 Series graphics card. We used discrete cards to achieve
consistent results across processors with and without integrated graphics.
Intel Core i7
Intel's top-end chips remain
unchallenged by AMD, but are beginning to look niche as Core i5s become ever
faster.
When the Core i7 first arrived in 2008, it
was the daddy of desktop CPUs - the processing pinnacle that only an enthusiast
would even consider buying. It still is to a certain extent, but since we
passed the point at which a Core i5 was powerful enough for most applications
long ago, does the i7 offer anything that makes it worth the extra cost?
Intel
Core i7
All i7 processors have at least four cores,
with the top i7-3900 series boasting six. Unlike the Core i5 range, however, these
cores are enhanced by Hyper-Threading so they can handle eight or 12 concurrent
threads. This is of limited use in most applications, but there are a few that
take full advantage of multithreaded optimisation: video-editing and 3D
rendering tools are the obvious examples. A Core i7 excels if you use demanding
applications such as Adobe Premiere Pro or Sony Vegas Pro every day.
Core i7 processors Turbo Boost to higher
clock speeds than their Core i5 siblings. This means, while the Core i5-2400 and
Core i7-3770S both run at 3.1GHz, their maximum Turbo Boosts differ: 3.4GHz for
the Core i5; 3.9GHz for the Core i7. The gap is smaller at higher speeds, but
is usually present.
Performance
A Sandy Bridge Core i7 is now lagging when
compared with newer, high-end chips. The i7-2600K scored 1.05 in our
benchmarks, barely faster than the 1.04 of a Core i5-3570K. It also has a much
higher power draw and costs $75 more, which makes it uncompetitive. The same
applies to the Core i7-2700K - its 1.08 score is beaten by the new low-voltage
i7-3770S, which is almost the same price. The former’s unlocked multiplier,
ripe for overclocking, is its only significant advantage.
Full-fat Ivy Bridge chips are much better.
The i7-3770 and i7-3770K scored an impressive 1.14 and 1.18 in our benchmarks -
the former for a $342 price that’s similar to those Sandy Bridge chips, and the
latter for $377 with the bonus of easy overclocking thanks to its unlocked
multiplier, denoted by the “K” suffix.
If you have an LGA 2011 motherboard, be
warned that the current trio of Sandy Bridge-E chips is lost in this company:
they’re either slower than similarly priced LGA 1155 chips, or faster but
prohibitively expensive.
The only reason to consider buying them is
their multithreaded performance. The $1,140 Core i7-3960X scored 1.14 overall,
but its 12 logical cores delivered a massive 1.65 and 1.47 in the video and 3D
rendering benchmark segments.
The verdict
Our favourites are the i7-3770 and
i7-3770K: the former is faster than its rivals for no extra cash, and the
latter is faster still with huge overclocking potential. The i7-3770S is a
worthwhile, energy-efficient alternative. Meanwhile, the top-end LGA 2011 parts
are ludicrously priced for their admittedly impressive performance, with no
premium placed on Ivy Bridge technology compared to the prices you’ll have to
pay for Sandy Bridge silicon.
The problem is that these chips are
overshadowed by increasingly impressive Core i5s. Stock performance is ample
for most people and, with some healthy overclocking, the i5-3570K will match
most of these Core i7s for less cash, albeit with fewer cores. That reaffirms
our belief that Core i7 processors are great for power users but overkill for
everyone else.
Know your sockets
Every Intel processor in this Labs uses the
same LGA 1155 socket except for three Sandy Bridge-E models. The Core i7-3960X,
i7-3930K and i7-3820 are only compatible with LGA 2011 - and despite using the
Ivy Bridge i7-3000 naming convention, they're actually Sandy Bridge parts.
The LGA 2011 socket was Intel's high-end
branch created exclusively for Sandy Bridge-E processors, although it's likely
that there will be Ivy Bridge-E models arriving towards the end of this year.
So while it's by no means the wrong platform on which to base your PC, be aware
that LGA 2011 will effectively limit your future upgrade choices to a small
group of Intel's most expensive enthusiast processors. For the vast majority of
users, LGA 1155 is the more sensible choice.
|
Model
|
Speed
|
Responsiveness
|
Media
|
Multitasking
|
Overall
|
Price (inc VAT)
|
Rating
|
|
i7-2600K
|
3.4GHz
|
0.99
|
1.11
|
1.06
|
1.05
|
$275 ($330)
|
4/6
|
|
i7-2700K
|
3.5GHz
|
1.01
|
1.14
|
1.09
|
1.08
|
$288 ($347)
|
4/6
|
|
i7-3820
|
3.6GHz
|
0.93
|
1.08
|
1.02
|
1.01
|
$282 ($330)
|
3/6
|
|
i7-3930K
|
3.2GHz
|
0.92
|
1.23
|
1.24
|
1.13
|
$510 ($614)
|
3/6
|
|
i7-3960X
|
3.3GHz
|
0.92
|
1.26
|
1.26
|
1.14
|
$950 ($1,140)
|
4/6
|
|
i7-3770S
|
3.1GHz
|
0.98
|
1.17
|
1.11
|
1.09
|
$287 ($345)
|
5/6
|
|
i7-3770
|
3.4GHz
|
1.03
|
1.22
|
1.17
|
1.14
|
$285 ($342)
|
5/6
|
|
i7-3770
|
3.4GHz
|
1.03
|
1.22
|
1.17
|
1.14
|
$285 ($342)
|
5/6
|
