Thread: The first CPUs of a next generation supercom power

Intel's Core 2 CPUs tossed aside the legendary Pentium name, but they also came with a brand new internal architecture and managed to outperform their predecessors while running at lower speeds and consuming less power. Now, after a two-year run of astounding success with its Core 2 Duo and Quad lines, Intel is ready to unveil their successors-the new Core i7, better known by its codename, Nehalem.

In keeping with Intel's tick-tock strategy, the Penryn CPUs released earlier this year didn't bring any major new technology into the picture, but were the same Core 2 CPUs die shrunk to a 45nm manufacturing process. Now with the process mature enough, Nehalem can launch, bringing huge architectural advancements. Core i7 is a curious name, but Intel suggests future CPUs will be named around it and everything will be perfectly logical going forward.

Under the heal spreader the Core 2 was a massive shift away from Intel's previous Netburst designs which the Pentium 4 was based on. In what started out as a project for laptops, Core CPUs were designed to be more efficient at lower clock speeds while still consuming less power and producing less heat. Nehalem retains those goals, but its main design goal was to eliminate bottlenecks between the CPU and the rest of the motherboard. Nehalem involves a complete platform change. For the first time, Intel has offloaded the memory controller from its usual place on the chipset northbridge to the CPU die. While greatly improving bandwidth, this prevents Nehalem CPUs from working with any Core 2 chipset. Only one version of one supported chipset is currently available-Intel's own X58-although motherboard manufacturers can opt to add an Nvidia nForce 200 bridge chip that will add native three-way SLI support for an added cost.

The most intriguing thing about Nehalem is its modularity. CPUs can be designed with features added or removed depending on the target market. Not only can the number of cores scale from two to eight, but the number of memory controller channels, type of memory supported and L3 cache size can be customized as well. The package size will change-current Core i7 chips use a Land Grid Array with 1366 contact pads, while lower-end ones will have fewer integrated components and therefore fewer pads. More interestingly, future Nehalem chips will have built in GPU cores. Also new to the architecture is Intel's Quick Path Interconnect (OPI) which replaces the front-side bus connecting the CPU to its chipset (or to other CPUs in a multi¬socket system). OPI is a high-speed, bidirectional link, with its speed measured in Gigatransfers per second.

The new Core i7-965 carries an Extreme Edition tag, while the 920 and i7-940 are regular desktop parts. All are native quad-core CPUs with 8 MB of L3 cache and a triple-channel DDR3 memory controller. The 920 and 940 run at 2.66 and 2.93 GHz respectively on a 4.8GT/s OPI, while the 965 runs at 3.20 GHz on a 6.4 GT/s OPI link.

Nehalem comes with expanded SSE instructions, improved virtualization, streamlined cache access, and power saving tweaks. Intel Dynamic Speed Technology is a sort of "Turbo mode" in the BIOS that is supposed to benefit non-multithreaded applications that don't use all the cores efficiently. Finally, Hyper-Threading resurfaces, giving each chip eight logical threads.



The mean machines We tested the Core i7-965 and Core i7-920, DX58S0 "Smackover" motherboard, and the hunky Thermalright Ultra-120 eXtreme RT cooler. We also received an 80 GB Intel X25-M solid-state drive to extract better scores. We used our own Kingston HyperX memory which can run at 1375 MHz with 5-7-5-15 timings. The graphics card was a 9800 GTX. We compared the performance of the Core i7-965 with a Core 2 Extreme OX9650 overclocked to match the specifications of the OX9770 at 3.2 GHz and a 1600 MHz FSB. We used an X48 chipset platform to test the OX9770-equivalent Core 2 CPU.

We ran both synthetic and real-world tests including SiSoft Sandra 2009, 3DMark Vantage and PCMark Vantage. These suites were used to benchmark the performance of the processors, memory, hard drive and graphics card. For real-world tests we compiled a suite of fully multithreaded applications including Cine Bench R10, POYRay 3.7 beta and x.264 MPEG4 video encoder. We chose WinRAR for the file compression test and AutoStitch for the image stitching test as these are known to not use all available cores to their fullest capacity. The reason for including them was to measure the performance boost achieved with Turbo mode enabled. The gaming test included Crysis and Call of Juarez which we ran at 1680x1 050 with medium settings and no AA. We configured the memory to run at 1066 M Hz in dual-channel with 7-7-7-20 timings for all the tests except for evaluating the performance of the Core i7-965 with three DDR3 sticks in triple¬channel. Let's head to the test results.

The scores after ensuring our test beds ran stably, we flagged off the tests. The turbo-charged QX9650 breezed through with stunning results, but we were amazed to see both Core i7s zoom ahead of even those record¬breaking speeds. At stock speed the Core i7-965 is around 25 percent and the Core i7-920 is around 10 percent faster than the QX9770. The difference in performance was most noticeable in the real-world tests. Crysis and Call of Juarez didn't show any notable difference-the frame rates improved by merely 3 to 5 fps.

The Core i7 shines with Hyper¬Threading enabled. After disabling Hyper-Threading in the BIOS the overall performance- dropped by 10 percent. We though't that adding another 1 GB DDR3 stick and upgrading to triple-channel would bump up the performance. However it was quite surprising to find out that the difference was not much. Next, we disabled the Turbo mode in the BIOS and found that the performance dropped by an average of 10 percent. Finally, we treated the Nehalem to a round of tests with the solid-state drive, which further increased the scores by 20 percent, with steroidal read and write speeds. It's hard to believe, but the drive can read data faster than 200 MB/s and write at around 75 MB/s! We managed to install Windows Vista in under 15 minutes an~ it took less than 20 seconds to boot into the operating system!

Final thoughts a luxury upgrade, while the 920 is a more reasonable choice .Things will be interesting when more chipsets and mid-range Core i7 CPUs are launched, and even more so when Nehalem chips with GPU cores come out late next year. Till then, Core i7 will appeal mainly to those looking for a killer high-end multimedia workstation and those who buy only the latest and greatest. Anyone who already owns a top-end Core 2 Quad Extreme Edition CPU won't benefit too much from an upgrade, especially if their main usage is gaming. Still, there's no denying that Intel has cemented its technology advantage and performance lead.