The first wave of excitement has already calmed down that emerged right after the first benchmark results of the new Intel processors on Core microarchitecture became public. We have really seen that the Core 2 Duo and Core 2 Extreme processors are currently offering the highest level of performance and that Intel truly deserves to be called the manufacturer of fastest x86 processors of today. The launch of new CPUs also known as Conroe pushed the formerly popular Athlon 64 X2 processors into the inexpensive mainstream solutions segment, thus changing the traditional market layout. The new Core 2 Duo turned into a true breakthrough compared with the Pentium D predecessors.

We have already discussed the details and peculiarities of the new Intel processor family in our previous materials:

• Contemporary Dual-Core Desktop Processors Shootout
• Intel Core 2 Duo E6300 + ASUS P5W DH Deluxe: Ideal Mainstream Platform?

At first glance it looks like the only drawback of the new processor family from Intel is their high price. Especially, since excellent performance is not the only advantage of the Core 2 Duo processors: they also boast comparatively low heat dissipation and power consumption as well as significant overclocking potential. However, in the choir praising the newcomer, there are a few voices that try to pinpoint the drawbacks of the new processor family that may theoretically slightly spoil its triumph in the market. One of the most insistent claims is the fact that the new Intel processors that have totally defeated all their competitors in the today's most widely spread benchmarks will not be able to repeat their success in 64-bit work mode.

I don't think I need to remind you that Core microarchitecture also supports 64-bit extensions Enhanced Memory 64 Technology (EM64T). This way Core 2 Duo processors become the first CPUs supporting x86-64 in the evolutionary chain including Pentium III - Pentium M ?Core Duo ?Core 2 Duo. In other words, the implementation of EM64T in the new processors is the first attempt of Intel's Israeli engineering team to introduce 64-bit extensions into traditional 32-bit processors.

However, you shouldn't underestimate the importance of the EM64T implementation. It doesn't really matter for the NetBurst based processors, since the 64-bit infrastructure has not yet developed well enough in the desktop segment. However by the time Core 2 Duo processors become mass, the situation should change dramatically. In Q1 next year we will all see new Windows Vista operating system. One of the key features of the new Vista OS will be the native support for 64-bit AMD64 and EM64T extensions. Although Microsoft will also offer a 32-bit version of its promising OS, we expect much high performance from the 64-bit Vista version, of course. The release of the new operating system is expected to become a powerful catalyst for the transition from 32-bit to 64-bit architecture. Moreover, the need for more than 4GB of RAM will also stimulate this transition.

However, the 64-bit operating systems from Windows family have already started their invasion. The currently available Windows XP Professional x64 Edition already can work with 64-bit applications and 64-bit processors supporting AMD64 and EM64T. However, it is still not so widely spread in the market because there are not too many 64-bit applications available yet and besides, this new 64-bit version is none other but a slightly modified 32-bit Windows XP professional, which is so far more than enough to satisfy most user needs. In other words, contemporary users do not feel the need to switch to 64-bit despite all the advantages of the AMD64 and EM64T such as linear addressing of over 4GB of memory and higher performance thanks to more general-purpose registers and their capacity. However, the practical value of these advantages is still quite hard to detect, because there are not that many desktop applications in the market that work really faster on CPUs supporting AMD64 or EM64T or that would use over 2GB of RAM, which is the maximum that 32-bit operating systems would allocate for a single process.

Note that from the micro-architectural standpoint, it is not that hard to implement 64bit extensions of the classical x86 architecture. x86-64 requires more general-purpose registers (16) with higher capacity (64bit), more 128-bit SSE registers (16) and linear 64-bit addressing. Of course, CPU developers need to apply some effort to implement the x86-64 support properly. However, they do not need to radically change the architecture, which is an indisputable advantage of the x86-64 compared with IA64, for instance, which has been introduced in Intel Itanium solutions.

That is why we would expect the relative performance of CPUs with AMD64 and EM64T in 64-bit modes to be not too different from that in?2-bit Windows XP. Therefore, most of the contemporary test sessions of the new Intel Core based processors were conducted in Windows XP Professional SP2. However, the emerging reports about the issues Core 2 Duo and Core 2 Extreme have in 64-bit work modes inspired us to resume our performance analysis and investigation ASAP.

Today we are going to share more benchmark results with you and make some conclusions about the performance of new Intel processors in 64-bit OS and 64-bit applications.