Intel Core i7: Boosting Nehalem Into The Turbosphere
Level 3 Cache, High Speed Cache Coherent Interconnect, 128-bit Math, On-Die Memory Controllers, String Processing Instructions, Turbo Core Controller, Scalable Hot Pluggable Bus and the return of the new and improved HyperThreading, this time with SSE 4.2 instructions. Whew... that's some feature list! And it's all packed inside the new Core i7 family of QuadCore 45nm CPUs, which is also known by its engineering moniker: Nehalem.
When HyperThreading was introduced in the old Netburst CPUs it seemed to be an interesting novelty but little more. It was fun to see two CPUs on the Windows Task Manager of your single core system, but since almost no software took advantage of it during those days, it remained in novelty stage and served very little useful purpose. However, HyperThreading goes with a multi core ecosystem like mustard on hot dogs, and it is with Core i7 CPUs that this feature is really going to shine. You will now see eight full cores on your Windows Task Manager even though you've only paid for four physical cores inside your i7.
You can rest assured that if your software is written for multithreaded applications, you'll be working at warp speed. Some of the more common and popular software that can take advantage of as many threads or cores as the system can accommodate include Adobe After Effects, Photoshop and Premiere; 3d Studio Max; 7Zip; AutoCAD; Bryce3D; DVD Shrink; Lightwave 3D; Macromedia Flash; Nero; Sony Sound Forge 7; and Winrar, not to mention games such as Call Of Duty 2, Oblivion, Quake 4, Supreme Commander, and benchmarking utilities like 3DMark. You may want to also note that both AMD-ATI and Nvidia graphics drivers are written as multithreaded, so if your video requirements call for you to squeeze the most out of your cards, HyperThreading will act as a rocket booster. Under the right circumstances, you can expect Core i7 to beat a Yorkfield (current 45nm Core 2 Quads) by 2:1!
Certainly the most news-worthy feature of the many incorporated into the Core i7 CPUs has to be that the Front Side Bus (FSB) which has been present on every Intel processor since the good ol' x86 days is now formally relegated to history. The Core i7 CPUs have replaced the FSB with Intel's own version of AMD's HyperTransport 3.0, which they call Quick Path Interconnect. There are many other ways that the Core i7 CPUs break new ground. They implement a completely innovative second level branch predictor, as well as a second level 512 entry TLB (Translation Look-aside Buffer) to catch anything that the first level TLB should happen to miss. Due to its improved parallelism over Yorkfields, Core i7 CPUs will be able to execute one third more micro-ops concurrently. It will also feature a speedier access for unaligned cache and much quicker synchronization primitives.
The Core i7 CPUs will also benefit from an energy saver feature which will be a complete departure from the current SpeedStep Technology which modifies the scaling of the operating frequency depending on the current workload. The new Turbo feature will dramatically speed the processing of single threaded apps by instructing individual cores that are not being utilized to be switched off completely. That capability allows additional power to be directed to the remaining cores which the software can access.
One of the most exciting aspects of Core i7 CPUs has to be that the cache hierarchy now features three separate levels. There will be as much as 8 MB L3 cache for each of the four processors, plus 256 KB of L2 and 64 KB of L1, equally split between instructions and data.
The current scuttlebutt calls for three Core i7 CPUs to be introduced by the third week of October, 2008. The Core i7 900 Extreme Edition will run at 3.2 GHz and feature 1x 6.4 GT/s Quick Path, while the Core i7 900 (I would dispute this "rumored" name as it's too similar to the significantly more powerful Extreme version) runs at 2.93 GHz and the Core i7 800 features a 2.66 GHz speed. The two non-Extreme CPUs feature a 1x 4.8 GT/s Quick Path, but all have a TDP of 130W and sit on a huge (by comparison to a current LGA 775) LGA 1366 socket. The "baby" Core i7 is the "sweet spot" as it is expected to sell for a street price of close to $300, contrasting with the $600 for the Core i7 900 and over $1000 for the Extreme.
Early benchmarks for the non-Extreme CPUs have shown a 3DMark Vantage score of almost 18,000 and production examples are expected to top 20,000. That is nothing short of amazing performance for $600 and $300!
Core i7: An astounding family of CPUs saddled with a profoundly silly name! I won't be tattooing it on my arm, but I sure as heck expect to be one of the first proud owners!