AMD Horus

The Horus system, designed by Newisys for AMD, was created to enable AMD Opteron machines to extend beyond the current limit of 8-way (CPU sockets) architectures. The Opteron CPUs feature a cache-coherent HyperTransport (ccHT) bus to permit glueless, multiprocessor interconnect between physical CPU packages but as there is a maximum of three ccHT interfaces per chip, the systems are limited to a maximum of 8 sockets. The HyperTransport bus is also distance restricted and does not permit off-system interconnect.

The Horus system overcomes these limitations by creating a pseudo-Opteron, the Horus chip, which connects to four real Opterons via the HyperTransport bus. As far as the Opterons are concerned they are in a five-way system and this is the basic Horus node (as called 'quad'). The Horus chip then provides an additional off-board interface (based on the InfiniBand standards) which can link to additional Horus nodes (up to 8). The chip handles the necessary translation between local and off-board ccHT communications. By building the CPUs around the Horus chip with 12-bit lanes running at 3125 MHz with InfiniBand technology (8b/10b encoding), this system has an effective internal speed of 30 Gbit/s.

With 8 'quads' connected together, each with the maximum of four Opteron sockets per node, the Horus system allows a total of 32 CPU sockets in a single machine. Dual and future quad-core chips will also be supported, allowing a single system to scale to over a hundred processing cores.

## See also

[edit]

* Heterogeneous System Architecture

## External links

[edit]

* Horus white paper. Archived 2006-01-13 at the Wayback Machine
* Google groups discussion by engineer.

* v
* t
* e

AMD processors

Lists|

* Processors
* K5
* K6
* Athlon
* XP
* 64
* X2
* II
* Phenom
* FX
* Ryzen
* Duron
* Sempron
* Turion
* Opteron
* Epyc
* APUs
* Microarchitectures
* Chipsets

Microarchitectures|

| IA-32 (32-bit)|

* K5
* K6
* Athlon/K7

|

x86-64 desktop|

* K8
* K9
* K10 (aka 10h)
* 15h
* Bulldozer
* Piledriver
* Steamroller
* Excavator
* Zen
* 1st gen
* Zen+
* Zen 2
* Zen 3
* Zen 3+
* Zen 4
* Zen 5
* Zen 6

x86-64 low-power|

* Bobcat (aka 14h)
* 16h
* Jaguar
* Puma

ARM64|

* K12 (aka 12h)

Current products|

| x86-64 (64-bit)|

* Athlon
* Ryzen
* Threadripper
* Epyc

|

Discontinued|

| Early x86 (16-bit)|

* Am286

|

IA-32 (32-bit)|

* Am386
* Am486
* Am5x86
* K5
* K6
* K6-2
* K6-III
* Athlon
* XP
* MP
* Duron
* Geode
* AMD Élan

x86-64 (64-bit)|

* Athlon 64
* X2
* II
* Sempron
* Turion
* Phenom
* II
* FX
* Opteron
* A-series APUs

Other|

* Am9080
* Am2900
* list
* Am29000
* Alchemy
* MIPS32

Italics indicates an upcoming architecture.
*[v]: View this template
*[t]: Discuss this template
*[e]: Edit this template