Introduction
Here are the specs of the latest Pentium Pro Chipset, just released from VIA. This chipset has the ability to defeat Intel for the first time since they released their Triton chipset. At present there is NO OTHER PPro chipset around that offers even slightly as much as this high performance chipset. If a high quality motherboard with that chipset should be out soon, I might even change my mind and get a PPro myself.
Actually I just found the first motherboard which uses the Apollo P6, it's the FIC PA-6010. Go and have a look! As soon as there's another new one out there, I'll tell you.
Features

High Integration
VT82C685 system controller
VT82C687 data buffer
VT82C586 PCI to ISA bridge
Six TTLs for a complete main board implementation
Flexible CPU Interface
64 bit Pentium-ProTM CPU interface
CPU external bus speed up to 66MHz
Supports Pentium-ProTM CPU multi-phase bus protocol for split transactions
Supports four level deep in-order-queue and deferred transaction
Supports APICTM multiprocessor protocol
GTL+TM bus driver and receiver compatible with Intel specification
Fast DRAM Controller
Sixteen level (quadwords) of CPU to DRAM write buffers
Sixteen level (quadwords) of DRAM to CPU read buffers
Fast Page Mode/EDO/Burst EDO/Synchronous-DRAM support in a mixed combination
Mixed 1M/2M/4M/8M/16MxN DRAMs
Supports 2-way bank-interleaving of 16MB SDRAM
Supports 2-way and 4-way bank-interleaving of 64MB SDRAM
6 banks up to 1GB DRAMs
Flexible row and column addresses
Optional bank-by-bank ECC and parity generation, detection, and correction capability
ECC with 1 bit error correction and multi-bit error detection capability
3.3v and 5v DRAM without external buffers
Burst read and write operation
5-1-1-1-1-1-1-1 back-to-back Burst EDO and Synchronous DRAM transfer at 66MHz
532MB/s peak transfer rate for Burst EDO and Synchronous DRAMs at 66MHz
266MB/s peak transfer rate for EDO DRAMs at 66MHz
BIOS shadow at 16 kB increment
System management memory remapping
Decoupled and burst DRAM refresh with staggered RAS timing
Programmable refresh rate, CAS-before-RAS refresh and refresh on populated banks only
Intelligent PCI Bus Controller
32 bit 3.3/5v PCI interface
Synchronous divide-by-two PCI bus interface
PCI master snoop ahead and snoop filtering
Concurrent PCI master/CPU/IDE operations
Synchronous Bus to CPU clock with divide-by-two from the CPU clock
Automatic detection of data streaming burst cycles from CPU to the PCI bus
Sixteen levels (double-words) of CPU to PCI posted write buffers
Byte merging in the write buffers to reduce the number of PCI cycles and to create further PCI bursting possibilities
Zero wait state PCI master and slave burst transfer rate
PCI to system memory data streaming up to 132MByte/sec
Sixteen levels (double-words) of post write buffers from PCI masters to DRAM
Sixteen levels (double-words) of prefetch buffers from DRAM for access by PCI masters
Enhanced PCI command optimization (MRL, MRM, MWI, etc.)
Complete steerable PCI interrupts
Supports CPU write-back forward to PCI master read to minimize PCI read latency
Supports CPU write-back merged with PCI master post-write to minimize DRAM utilization
Provides transaction timer to fairly arbitrate between PCI masters
Supports five PCI masters in addition to PCI-ISA/IDE/USB bridge
PCI-2.1 compliant
Enhanced Master Mode PCI IDE Controller with Extension to UltraDMA-33
Dual channel master mode PCI supporting four Enhanced IDE devices
Transfer rate up to 22MB/sec to cover PIO mode 4 and multi-word DMA mode 2 drives and beyond
Extension to UltraDMA-33 interface for up to 33MB/sec transfer rate
Sixteen levels (doublewords) of prefetch and write buffers
Interlaced commands between two channels
Bus master programming interface for SFF-8038 rev.1.0 and Windows-95 compliant
Full scatter and gather capability
Support ATAPI compliant devices
Support PCI native and ATA compatibility modes
Complete software driver support
Universal Serial Bus Controller
USB v.1.0 and Intel Universal HCI v.1.1 compatible
Eighteen level (doubleword) of data FIFOs with full scatter and gather capabilities
Root hub and two function ports with integrated physical layer transceivers
Legacy keyboard and PS2 mouse support
Plug and Play Controller
Dual interrupt and DMA signal steering with plug and play control
Microsoft Windows 95TM and plug and play BIOS compliant
Sophisticated Power Management and OnNow/ACPI Unit
Normal, doze, sleep, suspend and conserve modes
System event monitoring with two event classes
Two general purpose timers
Sixteen general purpose output ports
Seven external event input ports with programmable SMI condition
Primary and secondary interrupt differentiation for individual channels
Clock throttling control
Multiple internal and external SMI sources for flexible power management models
APM 1.2 compliant models
Extension to OnNow and ACPI (Advanced Configuration and Power Interface) support
PCI to ISA Bridge
Integrated 82C206 peripheral controller
Integrated keyboard controller with PS2 mouse supports
Integrated DS12885 style real time clock with extended 128 Byte CMOS RAM
Integrated USB controller with root hub and two function ports
Integrated master mode enhanced IDE controller with enhanced PCI bus commands
PCI-2.1 compliant with delay transaction
Four double-word line buffer between PCI and ISA bus
Supports type F DMA transfers
Fast reset and Gate A20 operation
Edge trigger or level sensitive interrupt
Flash EPROM, 2MB EPROM and combined BIOS support
Built-in Nand-tree pin scan test capability
0.5um mixed voltage, high speed and low power CMOS process
208 pin PQFP for VT82C685
208 pin PQFP for VT82C586
208 pin PQFP for VT82C687
Overview
The VT82C680 Apollo-P6 is a high performance, cost-effective and energy efficient chip set for the implementation of PCI/ISA desktop and notebook personal computer systems based on the 64 bit Intel Pentium-Pro super-scalar processors. The chipset supports multi-Pentium-Pro configuration with Intel GTL+ driver and receiver interface up to 66MHz external CPU bus speed. The chipset supports the Pentium-Pro CPU multi-phase bus protocols for split transactions, four level deep in-order queue and deferred transactions for optimal CPU throughput.

The VT82C680 chip set consists of the VT82C685 system controller, the VT82C687 data buffer and the VT82C586 PCI to ISA bridge. The VT82C680 supports six banks of DRAMs up to 1GB. The DRAM controller supports Standard Page Mode DRAM, EDO-DRAM, Burst EDO-DRAM and Synchronous DRAM in a flexible mixed/match manner. The Burst-EDO and Synchronous DRAM allows zero wait state bursting between the DRAM and the VT82C687 data buffers at 66MHz. The six banks of DRAM allow arbitrary mixture of 1M/2M/4M/8M/16MxN DRAMs with optional bank-by-bank ECC and parity support. The chipset supports sixteen level (quadwords) of CPU to DRAM write buffers and sixteen level (quadwords) of DRAM to CPU read buffers to maximize the CPU bus and DRAM utilization. The peak data transfer rate for the EDO and Synchronous DRAM (or Burst EDO) DRAMs is 266MB/s and 532MB/s, respectively.
The VT82C680 supports 3.3/5v 32 bit PCI bus with 64 bit to 32 bit data conversion. Sixteen levels (doublewords) of post write buffers are included to allow for concurrent CPU and PCI operation. Consecutive CPU addresses are converted into burst PCI cycles with Byte merging capability for optimal CPU to PCI throughput. For PCI master operation, sixteen levels (doublewords) of post write buffers and thirty-two levels (doublewords) of prefetch buffers are included for concurrent PCI bus and DRAM/cache accesses. The chipset also supports enhanced PCI bus commands such as Memory-Read-Line, Memory-Read-Multiple and Memory-Write-Invalid commands to minimize snoop overhead. In addition, the chipset supports advanced features such as snoop ahead, snoop filtering, CPU write-back forward to PCI master and CPU write-back merged with PCI post write buffers to minimize PCI master read latency and DRAM utilization. The VT82C586 PCI to ISA bridge supports four levels (doublewords) of line buffers, type F DMA transfers and delay transaction to allow efficient PCI bus utilization (PCI-2.1 compliant). The VT82C586 also includes integrated keyboard controller with PS2 mouse support, integrated DS12885 style real time clock with extended 128 Byte CMOS RAM, integrated master mode enhanced IDE controller with full scatter and gather capability and extension to 33MB/sec UltraDMA-33 transfer rate, integrated USB interface with root hub and two function ports with built-in physical layer transceiver, and OnNow/ACPI compliant advanced configuration and power management interface. A complete main board can be implemented with only six TTLs.
The VT82C680 is ideal for high performance, high quality, high energy efficient and high integration desktop and notebook PCI/ISA computer systems.