Intro
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Intel has very high-end research and development facilities – including development sites for several Intel CPUs – and chip factory in Israel, so we were pretty excited in traveling half the Globe just to attend the first IDF held in Tel Aviv. We expected to see more info on forthcoming Intel products and we hit bull’s eye: we could learn a lot more about new Intel CPUs, especially the new Merom/Conroe/Woodcrest family, the new Monahans cell phone application CPU and a little bit about the forthcoming 45 nm technology, since all these technologies are being developed in Israel.
At this IDF we could see a Conroe CPU prototype – which is the codename of the desktop CPU using Pentium M architecture that will replace Pentium 4 – and also an OEM notebook from ASUS based on the forthcoming Yonah CPU, which is the dual-core Pentium M manufactured on the 65 nm process.
Figure 1: Conroe CPU prototype.
Figure 2: ASUS OEM notebook based on Yonah CPU.
We had the chance of sitting and talking to Ron Friedman, Intel’s VP in charge of Intel’s MMG (Mobility Microprocessor Group) team, based in Haifa and which develops all Pentium M-class CPUs (Banias, Dothan, Yonah, Meron and even the next-generation 45 nm Intel CPU) and also the microarchitecture that will be used on desktop and servers starting next year.
The first successful commercial product from the Haifa team was Pentium with MMX technology (codenamed P55C, remember that one?) back in 1996. The next CPU development from them was a project codenamed Timna, a highly integrated CPU for the low-end market, which was cancelled when the product was finished and ready to go into production, basically because Intel decided to use the expensive Rambus memory with it.
From the Timna experience, however, came the expertise in projecting CPUs with great performance/power ratio, so they decided to go ahead with the project of a relatively low power CPU that would, at the same time, provide a great performance at lower clock frequency compared to desktop CPUs, codenamed Banias. This was 1999 and they didn’t have a clue what the market response would be, especially because at the time everybody was only trying to reach higher clock frequencies, without caring too much with consumption or heat dissipation. This CPU was released in 2003 as Pentium M and in fact it was so successful that Intel decided to use its microarchitecture on all next-generation CPUs, from mobile to server, which we are going to be talking more in the next page.
Friedman explained us that this decision had a lot to do with multi-core technology. For example, making a dual-core version of Pentium 4 “Prescott”, which can easily go around 100 W, is a pain, because theoretically its dual-core version would dissipate around 200 W. Even if the CPU dissipated 60 W making it double core would be very hard.
With Yonah, the dual-core Pentium M CPU manufactured in the new 65 nm process, ready to be released on the beginning of 2006, the Haifa team is now working on the 45 nm manufacturing process. Why shrinking down to 45 nm? According to Friedman, there are three basic reasons:
- Cost: With a smaller silicon die, Intel can have more CPUs from the wafer where the CPUs come from.
- Bigger cache: The big issue for memory cache is its size. On several CPUs the L2 cache is actually bigger than the CPU itself. So, reducing the size of the die it is possible to create a bigger L2 cache without increasing the size of the chip.
- Speed and frequency: A smaller die has its circuits closer, making it faster for them to communicate to each other.
The problem, however, is current leakage. Transistors have an inherent leakage problem. When transistors are turned off, they are not exactly turned off; they let a little bit of electrical current to flow. On old CPUs operating at high voltages this wasn’t a problem, because the leaked current would be negligible. On modern CPUs, however, not only the leaked current can be misinterpreted as if the transistor is turned on when in fact it is turned off, but also the leaked current is consuming energy, thus increasing the CPU power dissipation. So leakage is one of the enemies of lowering the CPU power consumption and heat dissipation.
