ASUS P4S8X SiS 648 Motherboard Review

ASUS P4S8X SiS 648 Motherboard Review - Page 2

ASUS P4S8X SiS 648 Motherboard
AGP 8X, Serial ATA and More!

By: Chris Angelini
December 16, 2002

Board Layout and BIOS of the P4S8X
Cocked, Locked, and Ready to Rock (and Overclock)

ASUS has a positive history of making board layout a priority and it shows on the P4S8X.  The board's back panel is a little unconventional; it sports PS/2 mouse and keyboard connectors, four USB 2.0 ports, one serial and one parallel port, an RJ45 10/100 Ethernet port, three 1/8" mini plugs for audio and a single IEEE 1394 Firewire connector. 

When Intel launched the Pentium 4, many prospective buyers were dismayed that they would have to replace their power supplies to accommodate the dedicated 12V power connector.  Most newer power supplies are already compatible with the corresponding ATX 2.03 specification, but for those that aren't, ASUS offers its EZ Plug feature that accepts a standard 4-pin power connector.  Further, the 20-pin ATX connector is located at the top of the board, conveniently located as to not interfere with airflow around the processor socket.  The P4S8X utilizes a two-phase power solution driven by Intersil's HIP6302 controller.


Officially, the P4S8X supports up to 3GB of PC2700 DDR memory through its three, 184-pin DIMM slots.  ASUS has equipped the board's BIOS with unofficial DDR400 settings as well, though.  As you can see from the above picture, an open DIMM slot easily interferes with the AGP interface, so you'll have to remove your graphics cards to perform a memory upgrade.  Although DDR333 with aggressive memory timings performs better than DDR400, we were able to get the memory bus stable all the way up to 410MHz.

SiS 963 South Bridge, Promise Serial ATA, and AGP warning light with passively cooled North Bridge

The P4S8X is an attractive offering because of the features ASUS includes.  In addition to the native ATA-133 support offered by SiS' 963 South Bridge, ASUS also includes Promise's PDC20376 Serial ATA RAID controller, which also supports an additional channel of ATA-133.  Realtek's RTL8201BL PHY interfaces with the 963 South Bridge to offer 10/100Mbps Ethernet and the Realtek RTL8801B PHY performs the same function for IEEE 1394 support.  It seems that ASUS is transitioning away from C-Media's 6-channel hardware audio, opting instead for the CMI9739A AC'97 6-channel codec.  Moreover, ASUS has added a few extra features on top of the previously mentioned EZ Plug.  EZ BIOS, for one, allows BIOS updating without having to boot from a floppy disk, ASUS POST Reporter provides voice alerts throughout the boot-up process and finally, an AGP warning light, which illuminates if a 3.3V graphics card is inadvertently installed.



ASUS' Award BIOS is straightforward and fairly simple to navigate.  And judging from the submenus, it is pretty clear ASUS intended the P4S8X to get the attention of the enthusiast community.  Voltage settings are available for the AGP interface (1.5-1.7V), the CPU (up to 1.75V), and the memory interface (2.5-2.7V).  Both the front side bus and memory frequencies can be set independently, the front side bus being adjustable between 100 and 166MHz in 1MHz increments and the base memory speed up to 400MHz (200MHz DDR).  Memory timings are also fully adjustable, allowing you to tune whatever memory you've purchased for maximum performance.  Then again, if you'd prefer to let the machine take care of that, you can always let the SPD chip arbitrate the timings.


The P4S8X supports AGP 8x, but that capability must be shared with the complimenting video card in order to utilize it.  So, if a GeForce4 Ti 4200 is installed, the board automatically defaults to AGP 4x mode. 


Unfortunately, the SiS 648 chipset does not support HyperThreading so there is no BIOS switch to enable the option.  In comparison, both VIA and Intel support the feature.


Given the sheer number of user-adjustable features in the P4S8X's BIOS, we were able to poke and prod the board until we found a reliable overclock.  Using a 2.2GHz Pentium 4, we adjusted the Vcore voltage to 1.7V and managed to coax 2.706GHz out of the processor.  At that speed, the PCI bus ran at 31MHz and the memory was operating at 328MHz (164MHz DDR).

Overclocking clearly shows notable performance improvements.  The botmatch demo is especially bound by processor performance, so it is no surprise that the overclocked platform takes a 21 percent advantage.  The flyby demo exhibits an equally impressive 19 percent gain, since at 640x480 the application relies more on processor performance that it does graphics aptitude. 


System Setup, SiSoft Sandra, and Unreal Tournament 2003

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