SiS Xabre 600
By: Dmitry Zinovyev
Price matters more than FPS
While reviewing 3D accelerators you are gradually getting used to the thought that so many fastest solutions, up-to-date graphic chips and pre-retail accelerator specimen are passing over your hands, which appear on the market in a few weeks after a card has settled on the test bed. You quickly get used to the good, and it's really painful to climb down from heavens to the sinful earth by having to change between GeForce 4 Ti4600 or Radeon 9700 Pro over to GeForce 2 MX. There are serious grounds the press has been blamed for dwelling too much at novelties and ignoring the commoner's needs. You can narrate Pentium 4 3.06 GHz for whatever long time while enjoying the pleasure of testing your hardware with 1 MB RAM on, but we've got to be aware that money-bags and enthusiasts are few while the vast majority of users are still at the pre-1GHz processors tormenting about squeezing extra ten FPS out of Doom III demo. What's the point in those bright colored PC cases with neon highlighting $200 a piece, especially if you hardly scratch up some cash for lunch...
Manufacturers can tell whatever tales of how fast a game will fly in 2003 on NV30 or boast hundreds FPS Radeon 9700 Pro today offers. But retail shops have always done and will do best just with on-the-budget solutions like GeForce 4 MX or competing boards. Every manufacturer dreams of biting off a heftier piece of the budget market, and indeed truly serious competition is on the up not about high-end products costing half a thousand bucks but about those whose price tags rank below $200.
The Xabre 600 chip
Two memorable events at once occurred on 25 November. First, it is the Moscow nVidia's live presentation of an NV30 working specimen with a dozen of brilliant demos run on it. Secondly, the information embargo put on SiS Xabre600 is up. This new low-end chip will replace the Xabre 400 covered in enough detail on the 3DNews pages. Before you delve into our Xabre 600 review, take some time running through the following materials:
 Testing Xabre 400 video cards
 Xabre400 Reference
Elitegroup ECS AG400
Gigabyte SP64D-H
Vinix VX-3340
PowerColor EvilXabre400
Meet Xabre 600
So what is it that makes this novelty differ from the former leader in the SiS line? This is primarily the higher core and memory speeds. The former attained 300 MHz, the latter - 600 MHz. What is more, Xabre 600 is the first real chip manufactured on the 0.13 mk process technology. nVidia will produce GeForce FX on the same technology, and unlike the Xabre 600 the leader of the graphics chip industry will hit the retail shelves no sooner than January or even in February. But Xabre boards will start appearing in shops already by the end of this year or early next year at the latest. The Xabre 600 will be followed by the Xabre II, which is expected already in February.
SiS Xabre roadmap
But let's not run forward. Mind you, the manufacturing process is not yet the most important thing. Let's outline the key features of Xabre 600 as compared with the competitors' chips:
|
SiS Xabre 600 |
SiS Xabre 400 |
nVidia GeForce 4 MX440-8x |
ATi Radeon 9000 Pro |
| Process technology, (mk) |
0.13 mk |
0.15 mk |
0.15 mk |
0.15 mk |
| Q-ty of transistors |
|
|
|
|
| Chip frequency |
300 MHz |
|
300 MHz |
|
| Memory speed |
600 MHz |
500 MHz |
550 MHz |
550 MHz |
| Memory type and capacity |
DDR 3.3ns
128 Mb |
DDR 4ns,
128 Mb |
DDR
128 Mb |
DDR
128 Mb |
| RAMDAC |
2x300 MHz |
400 MHz + external 125 MHz |
2x350 MHz |
2x400 MHz |
| Output to two monitors |
yes |
|
yes |
|
| AGP version supported |
8x (3.0) |
8x (3.0) |
4x (2.0) |
8x (3.0) |
| T&L Support |
yes |
yes |
yes (Superscalar) |
yes |
| Vertex shaders |
Vertexelizer Engine |
yes, v1.1 |
software-driven |
2 blocks, v1.1 |
| Pixel shaders |
|
v1.3 |
No |
v1.4 |
| Optional |
|
Support for stereo |
MPEG2 acceleration |
MPEG2 acceleration |
Now let's talk a bit about the chip architecture. The flow-block below gives a visual idea of the card's design:
Xabre 600 architecture
Paired with the new chip, the SiS301 provides the TV-out and output to a second monitor in exactly the same manner as Xabre 400 does. We'll provide more details of the chip below.
It makes sense outlining the key technologies used in the Xabre 600. First of all, it's the Vertexlizer Engine, the bandwidth optimization system XmartAGP, the images output control system XmartVision, the chip frequency control XmartDrive and the optimized Xminator II driver. The latter differs from the Xminator II in the support for the above listed technologies.
   
By sight and on the menu level, the driver does not make any difference to that bundled with the Xabre 400, so we won't dwell on it here. So, let's start telling of the Xabre 600 GPU with the Vertexlizer.
Traditional architecture of vertex shaders
Architecture of the Xabre 600 vertex shaders.
It's almost impossible to find any differences between the two flow blocks supplied with the SiS press kit. Judging by the drawings, the only difference for the case of Xabre 600 is in the name. In fact, the Vertexlizer Engine is a system in charge of the dynamical load distribution in vertex shaders between the GPU and CPU. All this allows SiS to claim - the vertex shader efficiency in Xabre 600 is rising as the CPU clock speeds go up, and at 2.8 GHz its efficiency is very close to that of nVidia GeForce 4 Ti4200:
One may start lengthy reasoning as to whether it is appropriate to use Pentium 4 2.8 GHz for a budget card or not. But that's not the point. SiS decided quite logically that for the budget system it makes sense trying to shift part of the load onto the CPU rather than implementing slow vertex shaders.
Next item on the agenda is the Xmart technology consisting of three components. The first, XmartAGP, is a system that automatically detects the AGP type of the system and based on the data decides which operation mode is the most efficient for the card. The second component is the XmartVision system that determines what the accelerator is doing at a particular moment. If it is busy outputting the 2D graphics in applications not requiring 3D, the system will make the image softer and nicer to the eye, which allows turning down the strain to the eyesight. If you start a 3D application, the driver will turn up the contrast and brightness making the image richer and more distinct. Basically, this resembles the 3Deep or similar utilities. What remains to be done is to verify in action how this technology affects the image quality.
The last Xmart-technology is the XmartDrive. At times when the system does not need maximum performance, the chip switches to the sparing mode and puts the frequency down, which prevents the chip itself from overheating and thus streamlines the system heating. This also increases the stability of both the accelerator and the computer on the whole.
 |
Top Stories: |
 |
|
|
MoBo:
| |
|
|
VGA Card:
|
|
|
|
CPU & Memory:
|
|
