The quick guide to Intel's Core i7
Everything you ever wanted to know in less than 2 minutes about Intel's Core i7 - you know, that CPU you've heard about.
The thing that strikes me about the Core i7 is that it’s not a game changer. That’s not to say it’s not a good processor, and a neat (though hardly revolutionary) upgrade to the Core 2.
It's just that Intel already had such a lead over AMD that this is really just rubbing salt into the wounds. The Core 2 was already well ahead of the Phenom on technology, and this just takes it a step further.
The long discussed Intel Nehalem architecture finally has an official name – Core i7 – and a street date. Officially launched on the 17th, there are already hordes of reviews online. As usual, one of our favourites is Atomic's first look, as well as Anandtech, which has one of its excruciatingly detailed benchmark reports online here.
For those that haven’t been following the announcements, the Core i7 has a number of new features:
An on-die DDR3 memory controller. Following AMD’s lead, Intel has put the memory controller on the CPU die instead of in the chipset, and this memory controller has a new twist – it’s triple channel (as opposed to the dual channel memory controllers common today). You’re best served by putting three separate DIMMs in your motherboard to take full advantage of this.
All cores on a single die – again, a la AMD. Current i7 processors have four cores, but processors with more cores are coming.
The front-side bus (FSB) is dead. All hail QuickPath, the new memory bus, which roughly doubles the memory bandwidth. Of course, the new bus also requires a new type of CPU socket.
Hyperthreading is back. Dropped from the Core 2 architecture, the Pentium 4’s hyperthreading technology makes a reappearance. Hyperthreading creates “virtual” processors to exploit thread level parallelism and keep the processors working at full capacity. Basically, at any given time a processor will only be using a fraction of its functional capacity. While the integer units may be working, for example, the SSE units in the CPU may be idle.
Hyperthreading helps the processor make use of more of that capacity by allowing multiple threads to access different portions of the CPU at once. It does, however, have the upshot of making your four-core processor look like an eight-core to the OS.
Funky new power management capabilities. Cores can be dynamically shut off if not needed, and can be slowed down when demands aren’t high. They’ll also slow themselves down if the processor starts to get too hot (though this can be turned off in the BIOS if you don’t mind running hot).
More than that, they can also dynamically run over the design clock rate if the processor finds that it’s cool enough to do so. This “Turbo Boost” technology is kind of like automated overclocking – if the CPU is cool, it automatically knows it can run faster and does so. Specifically, if the processor hasn’t reached its thermal limit and one, two or three cores aren’t operating at maximum load it can increase the clock speed by 133MHz. If only one core is under load, it can increase speed by 266MHz. In the Extreme edition, you can even adjust this somewhat, as well as change the thermal threshold. Again this can be switched on and off in the BIOS.
As mentioned, the i7 requires a new type of motherboard socket – LGA1366. You can’t stick an i7 processor in your old motherboard, I’m afraid. Currently, only motherboards using the X58 chipset from Intel support the Core i7.
AMD’s counter
AMD, meanwhile, has been trying to counter the i7 by talking up its own processor plans. Around the time of the launch of the i7, for example, AMD talked about the Phenom II and how you can theoretically get it to 6.3GHz using some totally impractical cooling methods.
The practical speeds will be considerably less than this, of course, though they’re likely to be a significant bump over Phenom speeds. A large part of this bump comes from the new manufacturing process. Phenom II is based on a 45nm process – which Intel has had for some time and has been using for several Core 2 processor models.
According to AMD, the Phenom II also boasts a number of other optimisations, including improvements to memory pre-fetch and branch prediction which will improve its operational efficiency (that is, get its actual performance closer to its theoretical performance) as well as allow high clock rates.
AMD has also announced support for DDR3 memory and the new AM3 socket in the Phenom II.
In spite of those improvements, I still expect it will lag behind the Core i7 architecture. In fact, as I’ve mentioned before in this column, the AMD processor I’m most interested is the Fusion, which may give it a chance to overtake Intel again. Fusion integrates a graphics core into the CPU, which may be a game changer for PC design. Of course, it could also be as slow as other embedded graphics solutions, which will result in it changing nothing. We’ll have to wait and see.
Other Blog Entries written by Nathan Taylor:
Thoughts on this article? Add a comment below.
Be the first to comment on this article.