An overview of Athlon
The Athlon is a powerful CPU, the first 7th generation CPU in my opinion. It was expected June 1999 but was delayed until August 1999. Intel's response (code name Willamette) was scheduled October 2000.
Athlon was designed using technologies from DEC Alpha 21064 and 2162 RISC processors. Their "farther" Dirk Meyer came to AMD and brought in an engineering team who succesfully developed the Athlon, which ended up being an enormous success to AMD.
Within the first months, the markets response to the Athlon was very positive. It seemed (as expected) to outperform the Pentium III at same clock frequency.
Let us look at what Athlon has to offer:
The first tests show this FPU performance:
|Intel Pentium III/500 MHz||2562|
|AMD Athlon /500 MHz||2767|
The use of the EV6 bus gives a lot more bandwidth than the Intel GTL+. This means that the Athlon has the capacity to work with new RAM types such as RDRAM. Also the use of 128 KB L1 cache is pretty heavy. The L1 cache is important when the clock speed increases and 128 KB is twice the size in Pentium II's.
The Athlon came in several versions. The "slowest" ones will have the L2 cache running at one third of the CPU speed, where the best ones (like "Thunderbird") work at full CPU speed (as the Xeons do). The Athlon was intended to give Intel competition in all segments including servers, where the topmodels are being compareable with the best Intel Xeon processors.
No system bus
Since the Athlon is not installed in the same way as Pentium II and III, AMD could develop a brand new architecture. This means that there really is no system bus. The Athlon module is connected directly to chipset's "North bridge" in the first edition through a 200 MHz data channel. In a multi-processor system, each CPU will have its own 200 MHz channel.
That channel connects only two units: the CPU and the chipset. In the P6 systems the CPU, L2-cache, RAM, PCI units, the AGP unit and the chipset are all connected to the system bus. In Athlon the traffic is split. North bridge comes first, then come RAM, AGP, the PCI units and the South bridge.
200,000,000 x 64 bit/ bit/second = 1.6 GB per second.
That was significantly better than Intel's present systems:
|System||Maximum total bandwidth|
|Intel 100 MHz||800 MB/sec.|
|Intel 133 MHz||1064 MB/sec.|
|AMD Athlon, 200 MHz||1600 MB/sec.|
|AMD Athlon, 400 MHz||3200 MB/sec.|
The new architecture opens up for new RAM interfaces. We will see support for 100 and 133 MHz SDRAM, for DDR SDRAM and for RDRAM.
It is also likely that we later can choose from 64, 128 or 256 bit wide RAM access.
Read about chip sets on the motherboard in module 2d
Read more about RAM in module 2e
Read module 5a about expansion cards, where we evaluate the I/O buses from the port side.
Copyright (c) 1996-2005 by Michael B. Karbo. www.karbosguide.com.