by R. K. Bloom

ABIT SI7-G chipset SiS R658

ABIT SI7-G chipset SiS R658

What time of RDRAM memory comes to a close, it became clear immediately after the announcement Intelom chipset 845D. Output i845E and i845PE chipsets only reinforced this assumption. As a result, the companys position RAMBUS was looking very sad: from day to day, the new dual-channel DDR system bundle will surpass the performance of i850 + RDRAM and the company will have nothing to sell (or take the royalties).

And the salvation of RAMBUS came from the direction from which it is least expected – the company introduced a chipset SiS R658, and announced the development of chip R659. At first glance it looks very strange desire of SiS to release chipset for high-end systems. On the other hand profits in this market sector is quite high, and brutal competition in any money making opportunity is attractive. As a result – SiS decided to fill the niche. To do so, was formed “working group”, which included SiS (as a manufacturer of the chipset R658), Samsung (who promised to provide the memory RDRAM PC4200 and PC4800) and Abit (which is pledged to make the motherboard).

The result of this union was the motherboard Abit SI7-G, which we now consider. However, before changes to the board, carefully consider the characteristics of the chipset.

SiS R658 chipset

To avoid confusion in the sequel of the material, I want to give some background information on the memory modules RDRAM. So, now sold in the market for memory types PC600 (already obsolete), PC800 and PC1066. Clock speeds are 300, 400 and 533Mgerts respectively. The modules have a 16bit interface and are designed to work on motherboards with chipset i850 (E).

In addition, in recent years began to appear RDRAM memory modules with a 32bit interface. To the buyer is not confused in the technical intricacies, it was decided had called these modules as follows: PC3200 and PC4200 (PC800 and PC1066, respectively). These memory modules are 2 times more contacts and physically compatible with the 16bit modules.

This memory can be installed only in a very limited number of motherboards (for example, ASUS P4T533 / R on i850E).

Finally, most recently appeared 32bit RDRAM modules with a frequency 600Mgerts. For them, the notation PC4800.

Another difference from 16bit 32 bit modules is that the organization of dual-access memory, we need two 16-bit or a 32bit module. However, when using 32 bit modules, we still need a special plug-terminator (in the photo – it is at the top).

Memory bandwidth PC800, running in 2 channel mode is 3.2Gbayts, PC1066 – 4.2Gbayts respectively. For 32 bit modules (which work in 2kanalnom default mode), throughput is 3.2Gbayts Memory PC3200 and 4.2Gbayts – for PC4200 (very convenient notation).

Now go to rascmotreniyu chip R658.

The most important difference between the SiS R658 chipset on i850 (E) is to support the bus AGP 8X. This fact should encourage users to buy new cards. However, it should take into account the fact that the real benefit from the use of AGP 8X is very small and the real growth rate observed in a very small number of applications.

Of course there are smaller differences. Since most motherboards on the i850 (E) equipped with the south bridge ICH2, which is unlike the south bridge SiS963 (which is included in the R658), has no support for UDMA133, and serial bus USB2.0 and IEEE1394 (“Firewire”). However, these differences are not significant: first, some manufacturers are bypassing the recommendations of the board Intela released on bond i850E + ICH4. And secondly, all the boards on the i850 (E) each have 5-6 PCI slots into which the user can install it needs expansion board.

Now we are interested in two questions: whether the chipset support for new processors with FSB 200Mgerts and whether this chipset processors with Hyper-Threading?

As for tires 200Mgertsovoy information is as follows: SiS R658 chipset officially does not support the new processors. Theoretically the user processor 200Mgertsovoy bus can take advantage of memory PC1200 (or PC4800 modules for 32 bit). But in this case may affect performance because the processor bus bandwidth will 6.4Gbayts and memory bus bandwidth – only 4.8Gbayts. In addition, the R658 chipset supports asynchronous operation of AGP and PCI, which allows them to establish nominal frequencies (66 and 33Mgerts, respectively) for any frequency FSB.

However, nothing prevents the SiS to release a new revision chipset with support for 200Mgertsovoy R658 tires, the more that acquired a license from Intel.

And as to support Hyper-Threading, it is present.

Thus, the functional diagram of the chipset:

Thus, the

  1. chipset supports Intel Pentium 4 and Intel Celeron processor with FSB 133 MHz and 100Mgerts.
  2. Official memory support PC800/PC1066 and PC1200. Dual-channel memory access.

South and North Bridge connected MuTIOL bus with a capacity of 6.1 Gbayts.

North Bridge supports AGP specification v3.0. In practice, this means support for video cards AGP 4X8X, and lack of support for older 3.3V cards.

SiS963 Southbridge is already familiar to us on surveys motherboards Gigabyte 8SG667 the SiS 648 chipset and Gigabyte SINXP1394 chipset SiS655.

Its characteristics are:

Support for ATA 33/66/100/133

Supports Serial Bus USB 2.0 (six ports).

Supports serial bus IEEE1394 (“Firewire”) – three ports.

Integrated 6-channel audio AC-97 (modem MC-97)

Integrated Network 10/100 Ethernet

As for the new chipset R659, it will support 4-channel RDRAM memory, capable of operating at frequencies from 400 to 667Mgerts.

Bottom line: if you look very carefully chipset specification, it becomes clear that he attributed to the high-end system is very complicated. You must have official support 200Mgertsovoy bus and memory bus bandwidth of at least 6.4Gbayts. As a result, R658 chipset can be called a “niche” product, which focuses on a small portion of users.