The Intel Pentium II ('Klamath') CPU

Introduction

As you can see, it will not fit into the Pentium Pro socket 8 and for the beginning it won't even go in any socket at all, since Intel will sell it as a unit together with its external cache in form of a slot card for the new 'Slot One'. It will come with the new MMX multimedia extension to its instruction set, just as the Pentium MMX and it will be released as a 233 and a 266 MHz version to start with.

Now what is it all about with the new Pentium II ('Klamath') and what can we expect from this new Intel CPU?

Facts About The Intel Pentium II ('Klamath')

• The Pentium II ('Klamath') doesn't include any second level cache anymore as its predecessor the Pentium Pro did. This is due to production costs, since in case only one portion of the die in the Pentium Pro (the CPU core or the L2 cache) is not functioning in the post-bonding CPU tests, the whole CPU has to be thrown away. The chips can only be tested after the bonding and at this stage it's too late to use one of the two components anymore.
  External L2 cache means less L2 cache performance. The Pentium Pro runs its internal L2 cache at clock speed, the Pentium II ('Klamath') will run its external special BSRAM (burst static RAM) cache only at half the clock speed, which makes this cache considerably slower than in the Pentium Pro.
• The external bus speed of the Pentium II ('Klamath') will still be only 66 MHz, the bus speed we know well from Pentium and Pentium Pro CPUs. Obviously Intel doesn't seem to plan higher bus speeds before the release of the next CPU, the Deschutes.
• The Pentium II ('Klamath') will come on a slot card for the new so called 'Slot One' motherboard slot. We all expected it anyway - we will need new motherboards for the Pentium II ('Klamath'). On this slot card there will be the L2 cache as well, which is planned to be 512 and later also 256 kB in size. Intel is planing to later on sell the Pentium II ('Klamath') without the slot card to some few selected OEMs. The old Pentium Pro can also be used on these new boards, via a special CPU card with a Socket 8. This CPU card can be manufactured by motherboard manufacturers, but they'll have to pay a considerable price for each card, since the 'Slot One' is patented by Intel.
• The CPU speed of the first Pentium II ('Klamath') will be 233 MHz and 266 MHz models will be following soon. This makes a multiplier of 3.5 x 66 MHz for the 233 version, with a multiplier of x1.75 for the L2 cache, and 4 x 66 MHz for the 266 MHz version, with a L2 cache multiplier of x2. On some exhibitions Intel has shown a Pentium II ('Klamath') at 300 and once even at 400 MHz (water cooled), but it's unclear at which speed the level 2 cache was running then.
• The Pentium II ('Klamath') will now have segment register caches, which will improve the poor 16 bit performance known from the Pentium Pro. Hence the Pentium II ('Klamath') will run 16 bit programs and mixed 16/32 bit OSs like Windows95 somewhat faster than the Pentium Pro.
• The first level cache of the Pentium II ('Klamath') will be increased to 16 kB data and 16 kB instruction cache. The Pentium II ('Klamath') will have more write buffers as well. These two things increase the L1 cache performance of the Pentium II ('Klamath') and help reduce the Pentium II ('Klamath')'s disadvantage of its slower external L2 cache.
• Due to fewer production costs, the Pentium II ('Klamath') could be even cheaper than the Pentium Pro. However, we'll have to wait for its release to be sure about this. I personally doubt this!
• Read the latest news about Pentium II ('Klamath') pricing and availability and Pentium II ('Klamath') voltage requirements !

Pictures Of The Intel Pentium II ('Klamath')

On this side there's a huge heat sink mounted on top of the CPU, which is covering the whole surface of the CPU card. It's mounted via the four holes around the CPU and kept with these two springs you can see below.