The catch-phrase for the Pentium 4 is definitely "memory bandwidth", and the ability of the motherboard chipset to provide it. The Pentium 4 processor simply devours system memory, and even the 533 MHz CPU models can overwhelm DDR400. The i850 and i850E supplied the necessary memory bandwidth through dual-channel RDRAM, but this is an expensive proposition and these chipsets are getting a bit long in the tooth, and do not support high-end features like AGP 8X. The solution was to provide a dual channel DDR chipset, while upgrading the feature set to the current high-end specifications.
The first such Intel chipset was the E7205, which provided a dual-DDR266 memory controller, AGP 8X, USB 2.0 and all the high-end fixings, and supplied the perfect base for 533 MHz Pentium 4 processors. This chipset has since been overtaken by the 800 MHz i875P chipset, but unless you're buying the uber-expensive Pentium 4-3.0C 800 MHz CPU, the E7205/533 MHz Pentium 4 combination offers a high-end solution that certainly won't break the bank. Until Springdale emerges, the E7205 occupies the mainstream performance end of the Intel line, with products like the AOpen AX4R Plus priced noticeably lower than comparable i857P motherboards.
The Intel E7205 chipset supplies a dual-channel DDR266 architecture and provides a great home for Pentium 4 533 MHz processors. The memory controller supplies 4.3 GB/sec of bandwidth, which exactly matches the CPU bandwidth of a 533 MHz Pentium 4 processor. The E7205 is also equivalent to the memory bandwidth of an i850E running PC1066 RDRAM, creating a similar performance platform for the DDR crowd.
Now that the 800 MHz i875P has been released, the E7205 is no longer the top dog for Pentium 4 DDR platforms, but remains a great pick for the standard 533 MHz Pentium 4. The design of the E7205's memory controller is a bit different than the dual-channel architecture of some competitive chipsets, such as the NVIDIA nForce (which features two distinct channels). Instead, the E7205 creates a single 128-bit "physical module" when a matched pair of DDR is installed, thereby doubling the overall bandwidth.
This format is simply a different angle to dual-channel memory, and has the same performance as two separate memory channels, except the E7205 has an expansive 4GB memory limit, and does not have the need for an arbiter chip. Installed DDR pairs don't have to be from the same manufacturer (though that's optimum) but needs to be the same size, speed and chip-count.
The dual-channel DDR memory controller is only part of the story, and the E7205 has a high-end feature set and includes support for the newest and fastest technologies. Some of these include AGP 8X, along with integrated LAN, Audio and USB 2.0 through the ICH4 Southbridge.
The following is a chart that offers a more detailed look at the Intel E7205 chipset design, its dual-channel memory architecture, bus speed support and integrated features:
This review will cover the AOpen AX4R Plus, a very impressive E7205 motherboard with all the fixings. We've looked over a few E7205 motherboards, but have found each lacking in one or more areas, but were pleasantly surprised by the overall features and options found on the AX4R Plus. Our evaluation will cover feature set, overclocking options, performance and overall value, so if you're looking for a high-end E7205 board with a mid-range price and overclocking to spare, then AOpen might just have the ticket.