Intel’s Smart Memory Access is yet another way Intel has increased the overall performance of ICM. In Smart Memory Access, Intel implements something they call memory disambiguation. Memory Disambiguation is something that allows execution cores to speculate what data is needed from the memory before it actually executes. This allows the system to “pre-load” information while the previous instruction is being executed, drastically decreasing memory latency effects.

The final improvement we see in ICM is the Intel’s Advanced Digital Media Boost. This feature is basically the end result of the doubling of the speed at which SIMD instruction sets are executed. Previously to ICM, execution cores had to break down the 128-bit SSE,2,3 instructions into two 64-bit subsets in order to execute them, allowing one SIMD instruction set to be executed per every two clock cycles. With ICM, the entire 128-bit SIMD instruction set is executed in the same clock cycle, allowing one instruction set to be executed every clock cycle. As a result of Intel’s Advanced Digital Media Boost, the end-user experiences dramatically increased performance when processing multimedia instructions.

Specific to the Core 2 series of processors, and probably every processor hereafter, Intel has included several very interesting features. They are:

• Intel Virtualization (VT) Technology
• Intel Extended Memory 64 Technolgy (EM64T)
• Intel Execute Disable Bit

Virtualization Technology is something we’ve been hearing about for quite a while now. The main idea for VT technology is to allow multiple applications to be running simultaneously under different profiles. The way it does this it creates “Virtual” platforms, or environments, and allows processes to run in those environments when the computer is actively being used on a different platform. The application of this technology is likely far more promising and relevant in the enterprise/business world as opposed to the average home user, but the potential for overall productivity increases looks very attractive.

EM64T, while previously implemented on the 600 series of the Pentium 4 line and later processors, will again be used in Core 2 processors from Intel. EM64T is essentially the means by which Intel processors operate on x64 instructions. It also allows Intel processors to utilize greater amounts of virtual and physical memory. There is nothing ground-breaking to report here.

Intel’s Execute Disable Bit is basically a further enhanced attempt at hardware-based virus protection. The Execute Disable Bit marks memory banks as executable or non-executable, depending on whether or not it is infected by a virus or other malicious agent. If the operating system attempts to read data from a non-executable piece of memory, this will be recognized and avoided, disallowing the spread of the virus.
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The only difference between the Core 2 Duo and the Core 2 Quad architecture is that Intel's Advanced Smart Cache feature does not work on it to the extent it does on Core 2 Duo. This is due to the fact that the cache on the processors is not pooled and used by all four cores. Each set of two cores, dies, has it's own cache bank which it pulls data from, and the two dies then have to communicate through the FSB link. This is far from ideal, and would be the main advantage of a "true" quad core processor.

Another difference between the Core 2 Quad and Core 2 Duo is power consumption. Where the Core 2 Duo carries a supposed thermal design power (TDP) of 65-75W, the Core 2 Quad, expectedly since it is two Core 2 Duos on one chip, carries a TDP of 120-130W. This is up there with the power consumption of the previous generation Extreme Edition chips, the 965 and 955.

The final, and one of the biggest differences between the Core 2 Duo and Core 2 Quad chips is that the latter will not work in all 965 and 975 chipsets. In fact, the Core 2 Quad apparently will not work in Intel's own X975XBX Bad Axe board. For this review, we had to use a brand new X975XBX2 Bad Axe 2 motherboard supplied by Intel.

By now we all know what ICM can do. We know that its implementation on the Core 2 family of processors has been nothing short of a resounding success. We know that the Core 2 Extreme X6800 is the fastest processor on the market. What we don't know is what kind of performance differences we will see with the Core 2 Quad. To get a definitive idea of what 4 physical processing cores are capable of, lots of testing has to be done. So, lots of testing we shall do.