i865 Chipsets

If the i875 chipset can be viewed as the logical successor to i850E, then its mainstream variant, the i865 chipset – formerly codenamed Springdale – can be viewed as the logical successor to the i845 series of chipsets. Not only do the i875/i865 chipsets represent a huge technological leap compared to their predecessors, but the performance gap between the pair of recent chipsets is significantly less than it was between the i850E and i845 family.

There is a clear trend in PC hardware towards parallel processes, epitomised by Intel’s Hyper-Threading technology. However, there are other examples of where performing several tasks at the same time is preferable to carrying out a single task quickly. Hence the increasing popularity of small RAID arrays and now the trend towards dual-channel memory subsystems.

Currently, there are two different strategies being employed in dual-channel memory controllers, one in which where each memory bank has its own memory channel and an arbiter distributes the load between them and the other to actually create a wider memory channel, thereby doubling up on standard DDR’s 64-bit data paths. In common with the i875P chipset, the i865’s Memory Controller Hub employs the latter, the same conditions for dual-channel operation also applying.

The i865 memory controller is the same as that used by the i875P chipset, supporting:

• Hyper Threading
• Dual 64-bit DDR memory channels
• Communication Streaming Architecture bus for gigabit Ethernet

and capable of being paired with either the ICH5 or ICH5R chip – which handles things like the 10/100 Ethernet interface, 6-channel AC97 audio interface, USB 2.0, the PCI bus, etc., to provide the following additional features:

• 8 USB 2.0 ports
• Dual independent Serial ATA ports

The ICH5R also provides software RAID for Serial ATA drives.

The upshot is that – unlike the i875P – i865 chipsets are available in three different versions:

• i865P: supports DDR266 and DDR333 memory only and doesn’t support the 800MHz FSB.
• i865PE: as per i865P, plus 800MHz FSB and DDR400 memory support.
• i865G: as per i865PE, plus Intel’s integrated graphics core.

While the i865G’s graphics core is the same as was featured on the i845G chipset, its performance will be faster, due both to a faster memory subsystem and a higher working frequency of the graphics core itself.

The following table compares a number of major characteristics of the i865P chipset with a selection of Intel’s other recent Hyper-Threading chipset offerings:

	i865PE	i875P	E7205	i845PE	i850E
Processor	Pentium 4	Pentium 4	Pentium 4	Pentium 4  Celeron	Pentium 4  Celeron
System Bus (MHz)	800/533/400	800/533/400	533/400	533/400	533/400
Memory Modules	4 DIMMs	4 DIMMs	4 DIMMs	2 double-sided  DDR DIMMs	4 RIMMs
Memory Type	Dual-Channel  DDR 400/333/266 SDRAM	Dual-Channel  DDR 400/333/266 SDRAM	unbuffered only  x72 or x64 DIMMs DDR SDRAM	DDR 333/266	PC1066  PC800-40 PC800-45 RDRAM
FSB/Memory  Configurations	800/400  800/333 533/333 533/266 400/333 400/266	800/400  800/333 533/333 533/266	533/266  400/200	533/333  533/266 400/266	533/PC1066  533/PC800-40 400/PC800-45 400/PC800-40
Peak Memory  Bandwidth	6.4GBps	6.4GBps	4.2GBps	2.7GBps	4.2GBps
Error Correction	N/A	ECC	ECC	N/A	ECC/Non-ECC
Graphics Interface	AGP 8x	AGP 8x	AGP 8x	AGP 4x	AGP 4x
Serial ATA	2 ports  ATA 150	2 ports  ATA 150	N/A	N/A	N/A
USB	8 ports  Hi-Speed USB 2.0	8 ports  Hi-Speed USB 2.0	6 ports  Hi-Speed USB 2.0	6 ports  Hi-Speed USB 2.0	4 ports  USB 1.1

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• i945 Chipset
• Intel’s 955X Express Chipset – Glenwood
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• A Comparison Chart of Intel’s Chipsets from 915P to P965