925x diagram Intel LGA775 Pentium 4 & 925X/915 Review

Intel 925X Express chipset is equipped with a performance enhancing feature just
like the previous 875P with Performance Acceleration Technology. The performance
enhancing feature maximizes performance by reducing latencies from CPU to
memory. However, Intel doesn’t provide an official name for this feature since
the performance difference with and without it doesn’t really worth touting.
Most manufacturers have chose to ignore it when marketing their boards.

Intel 925X Express chipset comprise of two main components: 82925X MCH and
ICH6/R/W/RW.
The 925X MCH is on FCBGA package measures 37.5 mm × 37.5 mm with 1210 balls providing
interface to the processor, main memory, PCI Express, and the ICH6. The ICH6
provides a numerous I/O related functions. The 925X MCH is optimized for the
LGA775 Pentium 4 processors supporting 800Mhz system bus only.

The memory interface of the 925X MCH supports 32-bit host addressing for decoding up
to 4 GB system memory, DDR2 controller with two 64-bit wide interfaces for
single or dual channel DDR2 memory, up to 8.5 GB/s peak memory bandwidth in dual
channel mode at DDR2 533, non-ECC and ECC memory. The 925X MCH contains a 16-lane PCI Express port for an external PCI Express graphics card operating at a
frequency of 2.5 Gb/s on each lane and supports a maximum theoretical bandwidth
of 4 Gb/s in each direction.
The 925X MCH utilizes the Direct Media Interface (DMI) as the chip-to-chip connection
between the MCH and the ICH6. This high-speed interface integrates
priority-based servicing allowing for concurrent traffic and true isochronous
transfer capabilities. This new bus delivers up to 2 GB/s concurrent bandwidth,
compared with up to 266 MB/s for the previous Intel hub architecture.

There are four different flavors of the ICH6; 82801FB ICH6, 82801FR ICH6R,
82801FW ICH6W and 82801FRW ICH6RW and all of them support 4 Serial ATA ports,
each providing 1.5 GB/s transfer rates, six PCI slots, 4 PCI Express x1 slots, 8
USB 2.0 ports, integrated LAN controller, AC’97 codec 2.3, Intel High Definition
Audio featuring eight independent DMA audio engines, Advanced Host Controller
Interface (AHCI) for native hot plug and
boosts performance with Native Command Queuing (NCQ) for faster boot times and
file transfers. Intel ICH6R and ICH6RW provide additional RAID support with
Intel Matrix Storage Technology. ICH6W and ICH6RW support Intel Wireless Connect
Technology2 with an integrated wireless Access Point (AP).