Every year, CPUs get faster. That's how PC technology rolls. But once in a while, a new processor comes along that slaps the market upside the head and forces a change in expectations in terms of value and performance. Intel's new
Sandy Bridge chips do just that.
They're game changers for both good and bad. For starters they're bonkers quick. The new quad-core Core i7 2600K is so fast, it makes Intel's six-core Core i7s look overpriced and silly.
Sandy Bridge also brings several new technologies to the table including a pukka fusion architecture - that's CPU and graphics processing on the same slice of silicon - and heterogeneous computing. If that sounds like digital double-speak it essentially means the new Sandy Bridge chips have specialised circuitry designed to do specific jobs, such as video encoding, faster than ever before.
Of course, Intel's Sandy Bridge processors don't make every other CPU on sale instantly redundant. But they do demand a reassessment of what represents both value for money and a sensible upgrade path.
If, for instance, you are currently running an older Intel Core 2 processor, does it make sense to build a new system based on the Intel LGA1,156 socket bearing in mind that Sandy Bridge chips require the latest LGA1,155 socket?
Likewise, while many AMD CPUs certainly offer superb value for money, the performance gap to Intel has now grown to truly epic proportions. Chips towards the top of AMD's price list certainly look precariously positioned.
Then there's the question of overclocking. It's disappointing that Intel has decided to severely limit overclocking with most Sandy Bridge chips. Even so, the unlocked K series are absolute screamers.
You could also argue Intel's latest chips are so powerful, overclocking is unnecessary.
The other major question Sandy Bridge poses is whether you need a discrete graphics card. For sure, if you're remotely serious about gaming, a pukka graphics card is essential. But for everyone else Intel's latest integrated video core is good enough for light gaming and has a superb 2D feature set. Time to reveal our thoughts…
If you're boning up for any kind of CPU upgrade or overhaul, you need to know about Intel's new Sandy Bridge chips. That's not because they're the only sensible choice. It's a question of context. You simply cannot judge the merits of other CPUs or appreciate the direction of PC technology development unless you understand what makes Sandy Bridge chips tick.
First, you'll need to identify the new Sandy Bridge processors in Intel's stupidly overcomplicated price lists. In its infinite wisdom, Intel has carried over the Core i3, Core i5 and Core i7 branding. Similarly, Intel has maintained the essential meaninglessness of those labels.
Yes, performance and features tend to improve as the number increases. But just like existing i3, i5 and i7 chips, there's no consistency. A Sandy Bridge Core i5 might have two cores. But it might also have four. Dumb.
Anyhow, the way you identify the new Sandy Bridge processors is the quadruple-digit '2000' suffix. Thus, the Core i5 2500 is a quad-core chip supporting four threads and an official clockspeed of 3.3GHz, while a Core i7 2600 is a quad-core chip with eight threads and a 3.4GHz clock. Got that?
At launch, there are 13 Sandy Bridge processors ranging from dual-core, quad-thread chips through to quad-core, eight-thread models. As if that wasn't baffling enough, some of those 13 launch CPUs are further distinguished by a suffix letter.
T and S series processors are low power variants. For instance, the Core i5 2500T is rated at just 45W compared to the 95W of the standard i5 2500.
Finally, there are the K series chips. Currently, there are just two, the i5 2500K and i7 2600K. They're identical to their letterless brethren save for one crucial feature, an unlocked CPU mulitplier.
As we'll see, thanks to Intel's new attitude to overclocking that's an extremely important distinction.
Subtle details
In terms of basic architecture, the CPU side of Sandy Bridge doesn't look that special at first glance. Intel is sticking with dual and quad-core models at launch with six and eight-core versions to follow.
Intel hasn't revealed launch dates for these more powerful chips, but we're expecting the six-core model in the second half of 2011 and the eight-core monster in 2012.
All Sandy Bridge processors are sired by Intel's most advanced 32nm production process, which is around half way through its two-year shelf life. Internally, Intel has overhauled Sandy Bridge's execution cores, netting roughly 10 per cent more performance per core and per clock cycle.
If that doesn't sound dramatic, Intel has seriously cranked up the clocks. That's not immediately obvious from the headline specifications. The top 2600K chip, for instance, is officially a 3.4GHz. That's only slightly quicker than Intel's performance king, the 3.33GHz Core i7 980X.
But here's the thing. The 2600K slots in at the high end of Intel's mid range. It costs about the same as the existing Core i7 875K, a 3.06GHz processor. That's not all. With Sandy Bridge, Intel has introduced the 2.0 revision of its Turbo Boost technology.
You can read our detailed thoughts on Turbo Boost 2.0, both good and bad, in the
2600K review. But for now, simply know this. In our experience, the 2600K runs at 3.8GHz regardless of how many cores are active. It's one quick puppy.
Raw CPU power alone would be enough to recommend the new Sandy Bridge family. And yet these chips have some seriously special sauce that has nothing to do with traditional PC processing.
Instead, Sandy Bridge breaks new ground in graphics. Firstly, it's the first bona fide fusion processor. That means it has both CPU cores and graphics processing on a single slice of silicon. It's all part of a broader trend towards system-on-a-chip (SoC) in all digital devices.
Smartphones are rapidly closing in on full SoC status and PCs won't be too far behind. Admittedly, it'll be a few years yet before the graphics core integrated into a CPU is good enough for proper gaming. But with Sandy Bridge, Intel has really lifted the game for integrated graphics.
The new HD Graphics 3000 core in the i5 2500K and i6 2600K is at least twice as fast as any previous integrated GPU. That's the good news. The bad news is that the HD Graphics 3000 and its 12 execution units is limited to those two models.
All other desktop Sandy Bridge processors make do with the HD Graphics 2000 and six execution units. What makes that really bizarre is that the other six execution units are indeed present in the other Sandy Bridge models. Intel, in its wisdom, has simply turned them off for marketing reasons.
Given that the 2500K ans 2600K are enthusiast-class chips with unlocked multipliers and therefore likely to be paired with discrete graphics cards, it's a crazy decision. If any Sandy Bridge processors really need higher performing integrated graphics, it's the lower end models that will end up in those set-top boxes and super-quiet media centres that could benefit from a boost in gaming performance.
Whatever, there's one further aspect to Sandy Bridge's near-SoC architecture and it involves another buzz term, heterogeneous computing. The idea here is that computer chips will increasingly combine both general purpose processors and purpose-built units capable of crunching particular workloads super fast thanks to hardware acceleration.
In other words, the future of PC processors is not more and more cores. In fact, it might well turn out to be the case that four traditional processor cores are enough for any future consumer-level computing task. But, courtesy of ever increasing transistor counts, those cores will be joined by a number a special-purpose units designed to tear through tasks like video encoding, encryption and, further out, perhaps even facial recognition. The specifics are hard to predict, but with Sandy Bridge, that process has started.
The relevant feature is the Quick Sync Video transcoder engine. Built into the integrated graphics core, Quick Sync Video combines dedicated circuitry with the parallel processing capability of the 3D execution units to deliver massive video transcoding performance.
Compared to even the immense software encoding capability of the Core i7 2600K, Quick Sync Video is at least three to four times quicker in comparable video encoding benchmarks. Then factor in the 2-4x performance advantage of the best Sandy Bridge chip compared to the likes of an old Core 2 Duo CPU and you have a double-digit factor performance improvement for video encoding alone.
Impressive as that is, Intel has made using Quick Sync Video thoroughly problematical thanks to limitations involving chipsets and discrete graphics. You can read more about those issues in the Core i5 2500K and and Core i7 2600K reviews. But the gist is that the people most likely to want to use Quick Sync Video are also the most likely to run into problems due to how Intel and the motherboard manufacturers have implemented the new features. It's pretty dumb.
The final part of the Sandy Bridge puzzle is overclocking. You could say Intel has spoilt us in recent years. After all, we've become accustom to 1GHz-plus overclocks on the majority of Intel chips. Just hop into the BIOS, give the baseclock a bump and say hello to 4GHz computing.
With Sandy Bridge, however, the party is over. The K Series chips aside, overclocking is limited to a maximum of 400MHz additional clockspeed using the partially unlocked CPU multiplier.
Admittedly, the K series chips are unlocked up to a theoretical 5.7GHz. But they're slightly more expensive chips - costing between £20 and £40 more than the standard model. The beauty of the old regime was that you could pick up a low-clocked cheapo version and crank it up to beyond-Extreme-Edition clocks. Those simple days are now over.
Down the upgrade path
If that's everything you need to know about Sandy Bridge, how does it plug into the CPU-upgrade conundrum?
Much depends on both the socket and CPU you are running. Starting with Intel platforms, the first thing you can do is disregard the LGA1,366 socket completely. In our esteemed opinion, it's a dead platform.
For starters, the only LGA1,366 chips that are faster than the best Sandy Bridge CPUs are the offensively overpriced Gulftown Core i7 900 series six-core models. Making matters worse, LGA1,366 is not long for this world.
When Intel brings out more powerful Sandy Bridge derived chips later this year with added cores, they'll come with yet another new socket, known as LGA2,011. Essentially, there is no upgrade path from a Gulftown processor.
Another easy Intel platform to deal with is any kind of quad-core processor in the LGA 775 socket. If your current rig fits that description, don't bother with a simple CPU upgrade. Either live with what you have for a while longer or go all the way with a Sandy Bridge based solution.
On the other hand, if you're running a low-clocked dual-core chip on LGA 775, you have more options. You could pick up a cheap quad-core Yorkfield CPU, such as the Core 2 Quad Q8300 and clock the twangers off it. We'd certainly recommend that option if it's gaming that really gets you going.
Alternatively, if video encoding is your bag, you might like to go for an AMD system based on one of the Phenom II X6 Thuban six-core processors. These can be had for less than £150. Factor in the typically low cost of AMD motherboards plus a little overclocking and you have a fairly funky encoding rig for a surprisingly low outlay.
As for owners of LGA1,156 systems, it's you we feel most sorry for. Intel has seriously shifted the boundaries in terms of price and performance with Sandy Bridge and we reckon it's shocking that LGA1,156 owners have been left behind.
To make it absolutely clear, we believe Intel could have architected Sandy Bridge to be largely or entirely compatible with existing LGA1,156 motherboards with few if any architectural compromises. Whatever the truth, the fact is there's nowhere to go for LGA1,156 users.
With AMD not currently offering anything to beat LGA1,156 systems, it's an all or nothing upgrade to LGA1,155. Sickening stuff given that LGA1,156 has been around for barely 18 months.
But what AMD systems? Traditionally, AMD pays a lot more attention to both the long term interests of its customers and backwards compatibility. Socket AM2 dates back to 2006 and yet all of AMD's current chips are theoretically compatible with AM2 boards and ye olde DDR2 memory.
In practice, your mileage will vary according to BIOS support. But there are plenty of old AM2 boards, for instance, that support the latest six-core Phenom II X6 chips. Therefore, if you have an AM2 or indeed an AM2+ board and a processor dating back to that era, it's extremely likely the most cost effective upgrade path will be an new chip from AMD. Hell, even if your budget is super-tight, you have options.
The Athlon II X4 645 quad-core is great for multi-threaded software if not so stellar for gaming. It's yours for under £90. A bargain in other words.
For AM3 owners, things are a little more complicated. If you already have a quad-core processor and gaming glory is your thing, a six-core Phenom II X6 isn't going to do much for you. In that case, you have two choices. Either you go turncoat and switch to Intel Sandy Bridge or you ride out the clock until the second half of 2011 and await the arrival of Bulldozer.
We won't know for sure until it's release, but it's currently looking like AMD's mythical Bulldozer architecture won't be compatible with the AM3 socket. Assuming your current system performance isn't getting you down, we'd be very tempted to at least wait and see whether Bulldozer delivers on the promise of a radical new CPU architecture before upgrading.
All of which means a few universal conclusions can be drawn. Firstly, both of Intel's LGA1,156 and LGA1,366 platforms should be avoided in terms of buying both a CPU and motherboard. Only LGA1,155 makes sense from Intel.
At the same time, AMD remains surprisingly relevant mainly thanks to the provision of lengthy backwards compatibility. It's a lesson Intel would be well advised to learn. That might just happen if AMD's upcoming Bulldozer chips really take the fight to Intel. Only then will Intel be forced to treat its customers right.
