Intel Core i (mobile) based laptops have hit the market. Core i replaces the formally high-end performer Intel Core2 series. Intel has been leading the innovation in low power processor chips since the Intel Atom and has incorporated those improvements into the Core i series. But there is more...
The Core i series for the mobile or notebook platform, also called Arrandale, has three main versions. The Core i3, the Core i5 and the Core i7. All of them have a minimum of 2 cores, minimum 3MB cache and a maximum power consumption between 35W-45W, which improves on the mobile Core2 baseline of around 45W-65W. All of them feature integrated Intel graphics (GPU) with HD video support on the chip which means the graphic chip is no longer external to the processor and motherboards can be built smaller. All of them support 64bit and Intel hyper-threading upto at least 4 threads.
Let us look at each of them in turn.
The main benefit of the Core i3 series over the Core2 is the low-power consumption, larger cache, integrated graphics and hyper-threading with 4 threads - which allows multi-threaded software to use the CPU more efficiently thus maximizing performance. The integrated graphics on the Core i3 are not at par with external graphics chips due to lower speeds but they do offer the chance of creating much smaller low power notebooks that can perform most tasks reasonably well. The lower power consumption and fewer chips mean less heat, less fan noise and significantly longer battery lives and all that at the same performance levels of mid range mobile Core2 processors! Enough to scare Netbooks into dark corners.
Core i5 takes everything the Core i3 has and adds Turbo Boost which is the Intel coined term for dynamic overclocking. To understand this you must understand that, in layman terms, processors today are limited by their power dissipation or TDP. A processor can only dissipate so much power, and if it starts dissipating more, then all manner of overheating issues crop up and eventually the chip shuts off or worse melts down in your lap. So chip manufactures have a problem on their hands, they must keep the processors power dissipation low - usually around 95W. So they can make a single core processor and increase its clock speed until it hits TDP 95W, or they can make a dual core processor but since the TDP is constant, the clock speed on each core must be lowered so that the net TDP of the chip is still under 95W, meaning each core can only clock up until it hits 47.5W. Of course if they design a quad core CPU then the clock speed on each core is further limited to hitting a TDP of only 23.75W. The moral of the story is that as the number of cores increases the speed of each core must be reduced to keep the total TDP on the chip constant. This is all good as long as all cores on the chip are busy working away and the chip is performing at its full potential. However in reality what happens is that at times one core is simply sitting idle. Now for a dual core chip with one core idle and the TDP of the other core limited to 47.5W, the processor is running at half its speed! Sometimes a core may not be idle but is also not running to its full speed because it is doing some low priority background job, again the other core could use the left over TDP and run faster. Intels Turbo Boost does exactly that. It is a clever little chip that monitors the TDP of each core and increases the speed of the busy core if it finds the other core is sitting idle. And it does all this dynamically and automatically overclocking and underclocking cores continuously monitoring the load on each core and all the time keeping the net TDP of the chip well within limits. I must admit this is quiet cool and the performance boost in multi-core chips is significant.
Another clever trick the Core i5 pulls is that it includes the integrated graphics chip into the Turbo Boost world (on mobile chips only). Which means if you run a graphic intensive application (like a game) then the GPU sees the higher load and boosted performance, while the CPU slows down. Alternatively, if you run a math intensive application, the CPU speed is boosted while the graphic chip slows down. This combination of CPU and GPU power make the Core i5 a significant performance jump above and beyond the achievements of the Core2. The Core i5 delivers the most balanced performance no matter what type of application you run and the graphics are fast. There is however a small niggle. The Core i5 loses on the benefit of the Core i3 in terms of low power consumption. The battery life of notebooks having the Core i5 is not therefore better than the Core i3.
This series is aimed at the very high performance market and adds higher frequencies and more options to the i5 feature set notably 4MB caches, hyper-threading with upto 8 threads and virtualization technology on some models.
So do the Core i series beat the Core 2?
This question is hard to answer in terms of raw performance. The lower end Core i3 series processors cannot beat the higher end Core2 Duo processors while the dual core Core i5 series performs at par with Core2 Quads. However in terms of technological improvements and power savings, the Core i series wins hands down. The integrated HD graphics on chip make it easy to support HD video playback without requiring an additional graphics chip. Expect laptops having the Core i series to run cooler and quieter and perhaps longer than the Core 2s. Also expect balanced graphics performance and smaller sizes. All in all the Core i is here to stay because it is does not simply retrofit old technology into a new brand name. It is genuinely new and has a lot of potential which Intel is sure to unleash in time.
Is it time to upgrade yet?
(At the time of writing) the answer depends on what you currently have. If you have a 2.2+ GHz Core2 Duo then you can still get some juice from your machine before you decide to upgrade. Anything lower and you will benefit from upgrading. Also I find there are very few compact chassis designs featuring the i5 and i7 processors. Most i5 and i7 series laptops are 15 inch or larger machines which beats the portability these processors can potentially provide. It seems that the manufacturers are still working on their compact chassis designs. So wait a while until the Core i series laptops arrive in their full portable glory.