SiS Xabre 600 Impressions

The graphics processor powering the Xabre 600 board is virtually identical to what was featured on the preceding Xabre 400.  Mainly, the core consists of four rendering pipelines, each equipped with two texture units.  Running at 300MHz, SiS claims the core is capable of 30 million polygons per second.  Similarly, the board features a theoretical pixel fill rate of 1.2Gigapixels per second, and with all eight texture units fully utilized, up to 2.4Gigatexels per second.  SiS' .13-micron manufacturing process is probably the most significant contribution to the Xabre 600.  Not only does the smaller process facilitate faster operating frequencies, but it also allows the Xabre 600 to run at 300MHz without a loud cooling solution or an oversized heatsink. 

SiS' reference board includes the 301 companion chip, adding support for TV-output (S-Video or composite), Digital Flat Panel output, and a second CRT connector.

SiS used 64MB of Samsung memory on the reference board we received.  Though the 2.8ns memory modules are theoretically capable of 350MHz, SiS operates the 128-bit memory bus synchronously with the graphics processor, at 300MHz.  As mentioned, there is an overclocking utility that provides the option to decouple the two clock frequencies, but our overclocking attempts met with mixed results.  We managed to hit 330/350MHz with SiS' own cooling solution and some thermal grease.  However, while some applications would demonstrate an increase in performance, others would show the opposite.  Hardly reliable results in that department.

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