The Best Thing That Could Happen To Intel’s Pentium 4 – The SiS645 Chipset – THG.RU

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The SiS645 Chipset” –>

Taiwanese Chipset Culture – More Than Just VIA …

Recent years made us almost forget that there is more than just one chipset maker in Taiwan. VIA was certainly able to get the most attention, since it started to attack Intel in 1999 with the early introduction of chipsets with PC133 and later DDR support. The other two, Acer Labs Inc a.k.a. ALi and Silicon Integrated Systems a.k.a. SiS lived more of a shadow existence besides VIA. Products with ALi or SiS chipsets were mainly found in low-cost systems and on less reputable motherboards. While in the past, high-end motherboards used to be equipped with Intel chipsets only, today you find a lot of quality boards with VIA chipsets as well.

SiS735 Chipset Changing The Image Of Silicon Integrated Systems

ALi has still not quite managed to step out of VIA’s shadow, even though a new revision of ALI’s ‘MagiK1’ chipset seems promising. SiS, on the other hand, was responsible for the biggest commotion in VIA’s management circles with the release of the SiS735 Athlon DDR chipset earlier this year. Not even we reviewers were able to believe our eyes as we saw the SiS735 chipset outperforming any other Athlon chipset at that time.

SiS had never been particularly famous for high performance and yet it was able to beat even AMD’s 760 chipset. Over night SiS had changed its image, while VIA’s engineers got their butts kicked badly by CEO Wenchi Chen, who had to face a lot of mockery for the fact that VIA’s KT266 had been crushed by a product from SiS.

Finally VIA Strikes Back With KT266A

Only a short while ago, VIA had finally proven to be able to take back the crown for the fastest Athlon chipset. The release of the Apollo KT266A chipset on the day before VTF 2001 in Taipei saw SiS falling back behind big VIA once again. The days before the KT266A launch hadn’t been that great either for SiS. First of all, motherboard makers and large OEMs had to be convinced that SiS735 was indeed a good product, unlike many other unsatisfying attempts of SiS before. Then there was competitor VIA, which gave motherboard makers certain financial incentives for dropping SiS and using VIA chipsets. Times remained difficult for SiS, but finally it had made itself a name that might be very helpful with the next product on the horizon, the SiS645 Pentium 4 chipset.

Legal Issues

First of all, unlike VIA’s Apollo P4X266, the SiS645 is perfectly legal. What does that mean? Well, VIA does not have an official license from Intel that would allow it to sell products that make use of the Pentium 4 bus. That’s at least Intel’s opinion. Wenchi Chen, VIA’s CEO, strongly disagrees. He doesn’t see how Intel could impose a license for the Pentium 4 bus in the first place, since car manufacturers don’t hold a license for ‘the road’ either. I personally couldn’t care less for this highly pathetic and unpleasant legal issue. What I do consider a nuisance however is the fact that ECS has been sued by Intel over selling P4X266 motherboards, while all the big Taiwanese motherboard makers are too chicken to provide their solutions. Intel is playing the big and bad Moloch again and basically a technological advance has been halted, because Intel ain’t willing or able to play fair. Nothing new really, or is it?

Anyway, SiS DOES have some cross-licensing agreements with the chip giant from Satan Clara, so that the Asus, MSIs, Gigabytes and other Taiwanese motherboard heroes can actually build and sell motherboards with SiS645 without having to fear legal trouble with Intel. The big chipmaker will still not like well-performing non-Intel platforms for its flagship processor Pentium 4, so we might still see motherboard makers refraining from supplying SiS645 platforms, simply because they are still afraid of Intel’s wrath.

The SiS645 Chipset –
A Breeze of Fresh Air For Pentium 4

SiS new and first Pentium 4 chipset looks already quite sexy just on paper.

The SiS645 North Bridge comes with the following features:

• Full Pentium 4 Support (Willamette/Northwood – Socket423 / Socket478)
• DDR SDRAM Support For DDR200, DDR266 and DDR333, up to 3 GB with 3 DDR266 DIMMs or 2 GB with 2 DDR333 DIMMs
• SDRAM Support For PC100, PC133
• AGP 4X Support, Fast Writes Support

The SiS961 South Bridge has the following feature list:

• ATA100 support
• Dual Independent Open HCI USB Controllers for up to 6 USB ports
• Integrated MAC controller
• AC97 compliant integrated 5.1 audio controller
• PCI 2.2 compliant, up to 6 PCI masters

Besides those features, SiS connects the 645 north bridge and the 961 south bridge with a new 16-bit wide interface, clocked at 266 MHz, which is called ‘MuTIOL’.

Similar to the StreamThrough-technology of NVIDIA’s upcoming nForce chipset using HyperTransport protocol between north and south bridge, the MuTIOL from SiS is also designed for multiple isochronous virtual channels. The 16-bit wide bus clocked at 266 MHz provides a bandwidth of 533 MB/s up- as well as downstream, which beats all other chipset interconnects so far. It is questionable if this high bandwidth is really needed today, but it’s always good to know you’ve got some headroom.

DDR333

Maybe not every one of you is familiar with the term ‘DDR333’. There have been too many different names for DDR-memory so far. The new double data rate memory supported by SiS645 is clocked at 333 MHz vs. the 266 MHz of the fastest DDR-DIMMs so far. DDR266 is also known as PC2100 memory, which comes from the fact that DDR-SDRAM provides a bandwidth of up to 2133 MB/s. DDR333 could therefore also be called PC2700, as its peak bandwidth is 2666 MB/s.

You can easily see that dual-channel RDRAM, as found in Intel’s 850 Pentium 4 chipset, is still providing the highest bandwidth. However, DDR333 is pretty close and coming with 25% more bandwidth than DDR266/PC2100 DDR-SDRAM. All SDRAM types benefit from a lower latency than RDRAM, which can make up for lower bandwidth in the majority of today’s applications.

Benchmark Setup

SiS645 is clearly armed with an impressive memory bandwidth that should be able to accelerate Pentium 4 to new DDR-memory performance heights. It might even be possible that SiS645 is able to reach or even pass Intel’s i850 chipset with its expensive RDRAM memory requirement. The good performance seen with SiS’s 735 chipset gives us hope that SiS645 might live up to our expectations. We also tested SiS645 with DDR266 memory, since we are not quite sure about the price and availability of DDR333 right now.

We tested SiS645 in the reference platform SS51A, as seen above, which proved to run extremely stable and reliable. In fact, this motherboard didn’t even crash once, neither did it show any other irregularities. It had to stand up against the fastest representatives of the i850, P4X266 and i845 chipsets, which were also tuned to maximum performance.

Benchmark Results

Sandra Stream Memory Bandwidth

In a test like this, it’s always good to start with the memory bandwidth, because it’s the major difference between the 4 players. You can see that the platforms equipped with DDR266 are scoring pretty much identically. This gives us a good hint that SiS645 equipped with DDR266 will probably perform pretty much the same as VIA’s Apollo P4X266. Once SiS645 is equipped with DDR333 memory however, it is clearly leaving the competition from VIA behind. At the same time, i850 and its dual-channel RDRAM can still not be reached in this benchmark. It’s also worth having a look at the mediocre results of i845 with PC133 SDRAM.

Sysmark 2001

i845 is far behind, while SiS645 with DDR333 is not quite able to reach the scores of i850. However, with 97-99% of the i850-scores its coming very close. VIA’s Apollo P4X266 is just about able to beat SiS645 with DDR266 memory.

Quake 3 Arena

In Quake 3 Arena, SiS645 with DDR333 is pretty much able to reach i850 scores, while with DDR266 it is slightly faster than VIA’s Apollo P4X266 chipset.

The same is valid for the NV15-demo, only that SiS645 is even able to beat i850 by a tiny amount.

3D Mark 2001

We can clearly see three different classes. The worst scores are of course generated by Intel’s slow i845 chipset. The next level is shown by the two candidates with DDR266 memory, while SiS645 with DDR333 is able to reach i850 scores once more.

Vulpine GLMark

GLMark shows the same behavior as 3D Mark 2001. Again, SiS645 plus DDR333 reaches i850 scores.

SPECviewperf

Those results prove that, under workstation conditions, i850 is still holding the lead over SiS645 with DDR333, but only a very small one. At the same time you can see that VIA’s Apollo P4X266 seems to have some kind of problem in LIGHT-04 and DX-06, where it falls well behind SiS645 with DDR266 memory.

FlasK MPEG

This test is a streaming benchmark and streaming applications want bandwidth. So it is not surprising to see i850 in the lead and SiS645 with DDR333 close behind.

Summary – Pentium 4 Wins Lots Of Attractiveness

Intel may like it or not, but i850 is slowly becoming obsolete. Today SiS has introduced a product that makes Pentium 4 more attractive than ever. The SiS645 also shows that all the claims ‘Pentium 4 needs RDRAM’ that I had contradicted so many times in the past are simply false. Pentium 4 doesn’t even need the 3200 MB/s of memory bandwidth provided by dual-channel RDRAM, as long as the 2666 MB/s offered by SiS645 and DDR333 are able to score the same benchmark results. SiS645 is THE i850 alternative for significantly less money.

The fact that SiS doesn’t have any legal battles with Intel over Pentium 4 bus licenses going right now, will ensure that many motherboard makers will soon provide SiS645 solutions instead of VIA Apollo P4X266 products, which carry the risk of getting them into legal problems.

SiS deserves to be greatly commended. The new SiS645 chipset was a pleasure to test, as it did not at all irritate with instabilities or incompatibilities. Who would have expected such a fast as well as solid product from a company that was expected to disappear or to be acquired by others very soon? Let’s now hope that SiS will get the attention it deserves. The SiS645 chipset is good enough to attract a lot of interest on its own, but SiS should make sure to provide up-to-date drivers and BIOS, a clean compatibility list and everything else that it takes to regenerate confidence in the slightly faded image of Silicon Integrated Solutions. I wish SiS all the best of luck!

VIA won’t welcome the introduction of SiS645 much. The battle with Intel is still going on and as long as this problem hasn’t been straightened out, the big motherboard players won’t start shipping platforms with P4X266. Now SiS introduced an even more attractive alternative. VIA will have to speed up this painful legal process as well as incorporate DDR333-support in its latest chipsets, so that it can strike back as soon as the legal battle is over.