Features of Core i7 on the Nehalem Processor

Core i7 is truly an amazing piece of silicon technology. One of its new features is Macrofusion. Macrofusion was originally implemented on the Merom and all it basically does is turn two instructions into one micro operation. In Core 2, macrofusion was limited to just 32 bit instructions but in Core i7 both 32 bit and 64 bit instructions are supported. What Macrofusion actually means for the average Joe is extra performance, done specifically by taking a TEST instruction and a CMP instruction and combining them into a single micro operation, but only if both instructions are followed by a conditional branch. So that little piece of information wasn't exactly exciting or understandable for most but Intel has assured the world at large that it will be very significant in the future. Another all important feature of Nehalem is its power efficiency.

Processors function at different states; namely P-states and C-states. P-states are all about performance while C-states are idle states and are therefore the subject of interest. There are seven C-states; Co is the active state for a processor, when you are clicking around in Windows your processor is happily in this state. When you walk away from your PC or decide to play a little solitaire on your multicore, the CPU will kick back to one of the six other C-states. C1 and C2 were developed in the early 90s and all they do is stop core pipelines and stop most of the core clocks. C3 will stop the remaining core clocks while C4, C5, and C6 will drop the core voltages which supposedly will reduce leakage and voltage reduction via shared internal chip voltage regulation (VR). In Penryn; the C6 state would reduce VR voltages only if all cores were idle, which was pointless if you had multiple cores and were only using one. Intel perfected the C6 state on the Nehalem and now each core will power down to such an extent that they would consume virtually no power at all. For the average desktop user this will be of limited benefit but for mobile users this means massive power savings. 

Intel giving free Performance?

Since power consumption is hardly a priority for desktop users, it is now time to look at performance, a realm where thankfully, the Core i7 really shows its worth. Intel has developed a dynamic performance increasing feature called Turbo Mode. 486 throwbacks aside, Turbo Mode actually does have a rather useful function. If you are running a single threaded application or an application that is not using all of the cores then the processor will crank up the frequency of the cores that are being used. The basic thinking is that while the total TDP (thermal design power) or basic maximum heat of the processor is a safety barrier that should not be crossed, if you are only using half of the available cores, then why not juice up the frequency and get more performance for your heat expenditure. The fact that Intel are increasing performance based on the TDP not being reached, shows that the silicon giant is doing a bit of lateral thinking and that the world of overclocking is about to receive a whole new continent. To add to the excitement, Turbo Mode does not only kick in when you aren't using all your cores, Intel in their seemingly endless wisdom has decided that should your processor not be hitting its TDP then it will happily increase its frequency across all the cores to get you more performance. For those people who crave even more performance Intel has made it a feature of X58 chipset motherboard BlOSes that the user can increase the TDP of the processor in the BIOS. Intel reckons that if you have purchased an aftermarket cooler that can deal comfortably with the 130W TDP of a Core i7 processor, then why not allow an increase the TDP of the processor to gain yet more performance?

While most overclockers would baulk at idea of letting a system overclock itself, there is a certain appeal to the idea of a CPU that can increase its speed without the use of software. Intel explained that Turbo mode is just a higher P state and that an older OS would not be able to take advantage of it, but that newer ones like Vista and XP would.

The Board

Core i7 will not be compatible with current motherboards simply because it won't fit. Intel has for the last 3 years been using the LGA775, this is a socket which has been used from the Pentium 4 across the board to the Xeon processors, but for Core i7 Intel had to change its design of the LGA to 1366 pins which means that the Core i7 processor is a bit bigger than a Core 2 processor. Intel have taken the redesign a step further by reinforcing the socket to handle much larger coolers because Core i7s TDP of 130W is not exactly arctic. The new X58 chipset with its ICH10 Southbridge will carry the usual six SATA2 ports, as well as eSATA, throw in twelve USB2.0 ports (time to bin those USB hubs), support for RAID 0/1/5/10, Gigabit and WLAN, and high definition audio. This list is nothing extraordinary but Intel has always opted for the idea of a stable feature rich platform and this is something people have come to appreciate. The ICH10 Southbridge will be replaced in the near future with the Platform Controller Hub (PCH) which will take over all the left over functions of the Northbridge and Southbridge as the processor takes on more of the traditional roles of the Northbridge. While this all might sound a bit complicated it will in fact lead to much cleaner motherboard designs and with a reduction in excess communication increased data transfer speeds.

Conclusion

Intel have knocked another one out of the ball park, and while we cannot reveal performance results witnessed firsthand we hope that our excitement about Core i7 carries through and that you can realize just how much of an impact Core i7 will make. Intel really have put in the homework with Core i7, that much is clear when you look the portfolio of new features ad improvements. They are also keeping the enthusiasts firmly in mind with a battery of overclocking features from better heatsink mounts to core specific tweaks. All in all the next few years look to be truly exciting and the second we can get our grubby paws on a sample you will see it right here.