Best CPU: 10 top processors reviewed and rated
13th Apr 2013 | 09:00
What's the best CPU for you?
This is it, boys and girls. We're nearing the end of days for the PC processor as we know it. There are storms of change on the horizon and it's anyone's guess what the PC will be like in hardware terms when it blows over.
Right now, things are much as they've always been. You pays your money, you takes your choice. In other words, you get to choose any CPU you like and match it with a motherboard and a graphics card. You've got both AMD and Intel options. And in many cases, you've still got full control over the chip you buy. You can overclock it, underclock it, swap it out and generally mess about with it.
Trust us on this - much of that could begin to disappear within the next 18 months, so enjoy it while it lasts.
If you're wondering why, there are a number of trends at work. Firstly, AMD's position is pretty precarious. We'll come to that in more detail later, but AMD is truly teetering on the edge of oblivion. Then there's the market's obsession with all things ultra-mobile and the technological trend towards greater feature integration that entails.
Very likely, it won't be long before you can't buy a drop-in CPU. They'll come soldered onto motherboards. So while we've a few complaints about the current state of play in CPUs, there's a chance we'll soon be looking back on this as a golden age in terms of choice and flexibility. So get out there and revel in it, we say.
There are some great CPUs from both AMD and Intel that can still be enjoyed in true enthusiast fashion. They're fully drop-in-able. They're tweakable. They're fun. And the way the CPU market is going, they'll probably keep getting the job done for at least a couple of years.
During the making of this CPU roundup, it felt like we were living on borrowed time. The PC is in a transitional period and five years from now much of what you take for granted when you spec up a rig will either be gone or very different.
There are two major drivers here: the trend towards ultra-mobile and AMD's failure to really stick it to Intel at the performance end of the market, even if it produces good chips for tighter budgets.
But let's start with that ultra-mobile mania. It explains why all of Intel's mainstream PC processors now contain on-die graphics. With any generation of computer chip, you have a given quantity of transistors available. That transistor 'budget' increases over time as manufacturing technology shrinks individual transistors.
In the past, it was pretty much all spent on improving CPU performance. More complex execution units, more cache, more cores, added features to help the cores like an on-die memory controller.
Already, however, that process has slowed. Intel's latest Ivy Bridge processors are a great example. At around 1.4 billion transistors for the quad-core version, such as a Core i5-3570K, Ivy Bridge is fully 240 million transistors bigger than the Sandy Bridge quad-core chip it replaced, but it doesn't have any additional cores or extra cache. Okay, the execution units are slightly tweaked, but we're talking typically low single-digit improvements in per-clock performance. That's not a lot to show for a 20 per cent increase in complexity.
The logical explanation, of course, is that Intel chucked almost all those 200-odd million transistors at Ivy Bridge's graphics core. The same thing will apply next year when the new Intel Haswell chips arrive. They will still be four-core beasts at best, and most of the increase in transistor count will be blown on improving the integrated graphics.
The problem is that, to date, Intel's on-die processor graphics has not been gaming worthy. In a mobile PC context, the power efficiency of integrated is great, but on the desktop and if you're into games, it's dead silicon. Worse than that, it means Intel is compromising processor performance - performance you'll actually use - in favour of improving integrated graphics performance that you won't use from crap to merely mediocre.
Eventually Intel's processor graphics will come good for gaming, but we're still several years away from that happening. Anyway, all this is because mobile computing is driving CPU design. Actually, that's not entirely the case - it's also because AMD hasn't stepped up to the plate.
AMD can't compete with the sheer raw performance of Intel's fastest current four-core chips in the LGA1155 socket. And that means it's nowhere near Intel's high-end chips in the LGA2011 socket. LGA2011 chips, of course, don't have processor graphics and are entirely focussed on CPU performance. But without AMD keeping Intel honest, LGA2011 chips are intentionally hobbled and very expensive.
Put it this way: if AMD had a competitive CPU, Intel's six-core LGA2011 CPUs would probably be half the price they are today, and there would also be eight cores on top. Put it all together and the unavoidable, undeniable conclusion is that Intel's desktop CPUs are already nothing like what they would be if Intel was simply focusing on performance.
But what of AMD? Well, that's an entirely different problem. And it's all to do with execution. Put simply, everything AMD has launched in the past five years has been too late and too slow. That's a great pity because AMD is more likely to sell straightforward CPUs in the configurations that desktop PC enthusiasts want. Plus, if those CPUs were more competitive, Intel would surely be forced to do things differently, too.
On the bright side
At this stage, we've painted a pretty bleak picture of the state of PC processors. But actually, things are still pretty good. You can still buy CPUs separately and mix and match them with motherboards and GPUs, allowing you to get the performance balance just so.
And AMD's chips are still competitive at certain price points, which has a knock-on effect across the market. More to the point, while it's likely CPU performance would be even higher if AMD had played a better game in recent years, of course today's processors are still extremely effective bits of kit. Intel may not have actually added cores to its mainstream chips, but it has done a very good job of improving per-core performance.
Sandy Bridge was a huge step forward in that regard and the latest Ivy Bridge processors raised the game a little further. All of which means that these are still the good times, right now. Five years from now, it's hard to say, but it's extremely likely you'll have a lot less choice, and year-on-year CPU performance increases may have slowed to a trickle - AMD may be a goner, for instance, and it's likely you won't be able to buy a stand alone CPU and drop it into your motherboard of choice. A few years after that, you may have to swallow motherboard, CPU and graphics in one big pill.
Back in the here and now though, let's enjoy what's on offer. If you're gaming mad, like us, the good news is that you don't need to go right to the top of Intel's current catalogue to get great performance. Intel's mainstream quads are still outrageously good. For those on tighter budgets, there are some very compelling options, some of which come from AMD.
If you've got a ton of cash, of course, there are even more options. In fact, we've thrown an Intel Xeon chip into the mix to show both how things might have been at the high end and also how you can get round Intel's increasing tendency to sandbag.
It's also worth noting that from a PC performance and gaming enthusiast perspective, now is a really great time to buy. Next year's Haswell chips from Intel are highly unlikely to bring dramatic increases in CPU performance. On the AMD side, we had hoped to see the company really raise its game next year, but now that's looking unlikely before 2014. If ever.
So it's fair to say that a decent CPU bought today will still be competitive for several years to come. As Arnie says, then, do it. Do it now.
This is a chip we're desperate to like. For starters, it's the most technically interesting CPU here. You've got AMD's latest Piledriver architecture and all its funky hybrid core technology. Then there's an AMD Radeon HD 7660D graphics, the most powerful integrated core on Earth.
In the end, however it's cold, hard numbers and practicality that counts, not intellectual niceties. On the latter point, the A10 falls at the first hurdle. Thanks to that integrated graphics core, it has different pin-out requirements to other AMD chips. And that means a unique socket, known as FM2.
That's a bit of a bummer because it means you can't buy an A10-based system and retain the option of upgrading to heftier hardware later on. And trust us, pretty soon you'll want heftier hardware.
There's nothing we love more than a giant-killing budget special. So, the AMD FX-4300 ought to be right up our alley with its double-digit price tag. But the problems begin as soon as you look at the price.
The gap to the FX-6300 is a little bigger in AMD's own price lists. But in the end, what matters to us (and, obviously, to you) is full retail pricing. And as we go to press, the 4300 just happens to be under £10 cheaper than the 6300.
If the 4300 was just clocked a little slower or short on cache, that might actually make sense. You could clock it up and spend that tenner down the pub. In reality, however, the 4300 is missing a pair of cores and that really is awfully hard to make up for.
Picking between the AMD FX family is mostly about making finely balanced judgements on performance and price. Well, it is when you compare this six-core FX-6300 with the eight-core 8350.
As those who read from top to bottom will already appreciate, the quad-core 4300 pretty much implodes by virtue of being far too close to the 6300 on pricing. So, in AMD terms, it's 6300 versus 8350. Time for a fight.
For gaming, it's a knock out in the first round. After much gameplay, we can confirm that the 8350's extra cores don't land any punches, so the £50 premium is hard-earned money much better invested in a faster graphics card.
Per-core performance. Single-threaded grunt. Instructions per clock. Call it what you will, but the amount of work done by a single core each cycle is AMD's big problem right now.
Of course, defining what a core is has become a little murky since AMD released the Bulldozer architecture in late 2011. With shared floating point resources for each pair of integer units, you can argue this chip is both quad-core and eight-core. In reality, it's somewhere in between.
Like the other AMD FX chips, the 8350 has the new-specification Piledriver cores. But they're only a fairly minor derivation of Bulldozer, so AMD's best hope with this generation was always going to be clockspeeds.
Intel Core i3-3225
Once upon a time, during one of the golden ages of home-brew computing, the difference between a high end CPU and a £100 poverty chip was nothing that you couldn't fix with a big fan, some thermal paste, and maybe a pencil. If you want to know just how much things have changed. Look no further than the Intel Core i3-3225.
The poverty stricken bit it's got nailed, even if £109 isn't exactly chump change. But the sad fact is that there's nothing you can do to bridge the gap between the 3225 and even a mid-range chip like the Core i5-3570K, much less a six-core Extreme processor or the outrageous £1,500 Xeon monster.
Intel Core i5-3470
The Intel Core i5-3470 is a pain in the arse. In many ways, it's a very compelling chip that offers nearly everything you get with the Core i5-3570K for a little less cash. So it puts you in a real quandary. Should you spend £145 on the 3470, or should you pony up £175 for the 3570K?
For some the answer is actually pretty easy. If you're absolutely sure you're not going to overclock your CPU, go for the 3470. The stock clock comparison is 3.2GHz nominal and 3.6Ghz Turbo for the 3470 and 3.5Ghz nominal, 3.8GHz Turbo for the 3570K.
In either case, you get quite fabulous single-threaded performance, very good multi-threaded throughput and gaming that's about as good as it gets. In fact, in the here and now, it's all you need for quality gaming.
Intel Core i5-3570K
The marketing men of Intel don't half wind us up. But there is one upside to the endless artificial variants on Intel's Ivy Bridge micro-architecture theme. There's bound to be something that fits into just about any usage-model slot you can think of.
When it comes to gaming, that something is undoubtedly the Core i5-3570K. It's the full quad-core Monty, none of this dual-core, quad-thread nonsense served up by cheaper Core i3s and indeed one or two Core i5 models. What it doesn't have is HyperThreading, so it's not the sharpest tool in the box when it comes to heavily threaded apps like video encoding.
To put that in context, it's no slouch. Indeed, it's quicker than a six-thread AMD FX processor in Cinebench and x264 HD video encoding.
Intel Core i7-3770K
There are some things in life you really want to hate. Like massively successful people. Or new variants of the Porsche 911 with electric steering (sorry, that one will probably take a bit too much explaining). But then they turn out to be really nice and amazing fun to drive. And you just bloody well can't.
That's pretty much the case for the Intel Core i7-3770K. At around £250, it's over £100 pricier than the Core i5-3470. But it's based on precisely the same silicon. The main difference is that Intel has flicked a few switches, fully exposing the Ivy Bridge architecture's goodness.
So, you get HyperThreading and thus a grand total of eight threads. The CPU multiplier has been fully unlocked, too, so you can clock the twangers off it at whim. And the cache has been fully enabled, so you've got the full 8MB.
Intel Core i7-3970X
High-end CPUs used to be a tough sell back when Intel produced a single processor core and simply differentiated with clocks and cache. There wasn't much you could do about the latter, but overclocking a budget chip usually produced something surprisingly comparable with the flagship Extreme effort.
Then Intel started doing things differently - like the six-core Gulftown chip. With an extra pair of cores and a unique triple-channel platform, it was a different proposition from Intel's mainstream desktop CPUs.
Intel's high-end platforms have been thinly disguised workstation-cum-server tech - that's added complexity and cost in areas that don't benefit desktop users. And yet, you could still argue that they're something special.
Intel Xeon E5-2687W
Eight cores. 16 threads. This is the way Intel's Sandy Bridge-E was supposed to be. But it's only available in Xeon trim.
You could ask what's in a name? After all, the Intel Xeon E5-2687W will drop into any old X79 motherboard, just like a Core i7 desktop processor. So if you want the full eight cores, you can have them. But that Xeon moniker comes with a pretty punitive price tag. In this case, we're talking £1,450. If that seems ridiculous, it probably is.
However, in Intel's defence, Xeons are aimed at a different market. In the desktop context, that means you're paying for redundant features, most notably validation for enterprise workloads. The other unwanted corollary of the Xeon's workstation-ness is that it's irreversibly locked, so you can't adjust the CPU multiplier.
Benchmark analysis: It's all about the numbers
Picking some of our benchmarks is easy enough. The x264 HD test is a great guide to video encode performance. It's straight in. Cinebench gives a glimpse of how CPUs perform in professional applications which major on threading. Stick that on the list.
Memory bandwidth is interesting in terms of the insight it gives to platform scalability and, therefore, makes the grade. Then there's power consumption, which will split opinion in terms of its relevance on the desktop. At the very least, it reveals the underlying efficiency of a CPU architecture.
Of course, we're big fans of overclocking so that's a critical benchmark. All of which just leaves the critical matter of gaming. With so many game titles out there, what do you go with?
Well, World in Conflict has several things going for it. It's scales well with CPU performance, for starters. Just as important, it's got a thing for single-threaded grunt. That's not to say extra cores have no impact. But you need beefy cores to get the best from it.
Given that several of the other benchmarks we use give a good guide to multi-threading performance, World in Conflict provides that critical worst-case scenario in terms of games that need strong per-core performance.
And the winner is… Intel Core i5-3570K
The computer industry has become obsessed with ultra-mobile. Eventually, that's going to do horrible things to the desktop PC. It's already putting a cap on desktop CPU performance.
The good news is that the worst has yet to come. Today's CPUs still offer almost all of what we really care about. There's configurability in terms of sockets. There's overclockability from all of AMD's chips and some of Intel's. And there's no shortage of choice.
This month, we've chips ranging from two cores and sub-£100 all the way up to eight cores, 16 threads and nigh on £1,500. We're still in the golden age of desktop computing, even if it is the dying days.
The joker in this pack is AMD's A10 Fusion chip. It sits alone in this test by virtue of a unique CPU socket that's a function of its integrated graphics. That makes it a very different proposition from a chip that can drop into any old AM3 motherboard and that takes it out of the running. It's an interesting chip for media centre larks. But it's not a serious player in the mainstream desktop game.
As for the rest, the AMD FX-4300 is first up against the wall. That's not because it's a particularly bad processor. It's just not cheap enough in comparison with others.
We're not crazy about the Intel Core i3-3225, either. It's quite pricey for a dual core. And you can't overclock it, which is a major downer.
Then there are the two big-iron chips on the LGA 2011 socket from Intel: the Core i7-3970X and Xeon E5-2687W. They are both absolute beasts. And they're both silly money, unfortunately. If you've money to burn, fair enough, they're spectacular performers.
From here on in, it's very tight indeed. In fact, of the remaining processors you can make a convincing argument for every single one being our overall winner. The Intel Core i7-3770K, for instance, is a monster. It's insanely quick for a quad-core chip. And you can have that performance on the sensible LGA 1155. But if you're a bit game-obsessed, like we are, it's hard to justify the £250-plus price tag. It simply won't deliver more tangible in-game performance than either of the Core i5 chips. So it's goodbye to the 3770K.
Next up is a three-way tie for second place between the AMD FX-6300, the FX-8350 and the Intel Core i5-3470. Depending on your budget and what you like to do with your system, any of these three could be your perfect processor partner.
As ever, we lean towards game performance, so the Core i5 gets our vote. All of which leaves the Intel Core i5-3570K with the spoils of victory. Yup, it's a tediously predictable result. And not one we can justify in objective terms. We know that £30 is a lot to pay for what amounts to an unlocked CPU multiplier. We wish Intel didn't do things that way. But it does, we want that extra control and we're willing to pay for it.