Original Link: https://www.anandtech.com/show/951
SiS 648 - Taking Advantage of the P4 Situation
by Anand Lal Shimpi on July 22, 2002 6:09 PM EST- Posted in
- CPUs
Aside from NVIDIA, there isn’t really much competition that VIA faces in the Socket-A chipset market. With NVIDIA shipping very small quantities of their chipsets, things are very quiet on the Athlon front, but why? ALi has made a few failed attempts at the desktop chipset business recently but VIA’s most capable competitor, SiS, is hard at work in a different part of the market.
SiS is the only 3rd party manufacturer other than ATI to have an official license from Intel to produce chipsets for the Pentium 4 platform. Although VIA engineered a perfectly fine chipset without obtaining this seal of approval, they are having a very hard time selling their P4X series of chipsets because of the chipset’s questionable legality. With ATI focusing mostly on the mobile side of the market, SiS is left to produce all of the more cost effective Pentium 4 chipsets.
It should be no surprise to anyone that SiS spends the vast majority of their time keeping their Pentium 4 line fresh as they have an effective exclusive on the 3rd party desktop Pentium 4 chipset market. In the past nine months SiS has released no less than five Pentium 4 chipsets, including today’s release of the SiS 648.
The 648 chipset continues SiS’ Pentium 4 line by updating the 645DX chipset to support AGP 8X along with a new South Bridge. The improvements to the technology are minimal but seeing as how we haven’t taken a look at a SiS P4 chipset since the original 645 we thought we’d give the 648 a once-over to see how things have changed.
648 North Bridge - A Mild Improvement
The main improvement the SiS 648 North Bridge offers over the 645DX is its support for AGP 8X. With SiS putting so much effort behind their AGP 8X compliant Xabre GPU it makes perfect sense for them to migrate all of their chipsets to AGP 8X versions.
Other than the AGP 8X controller, the North Bridge remains relatively unchanged from the 645DX. The memory controller only officially supports DDR266 and DDR333 however it should work fine with DDR400.
According to SiS, a DDR400 version of the chipset will be out later this year, most likely after much heavier validation with DDR400 memory.
The 648 North Bridge supports both 400MHz and 533MHz FSB frequencies.
| North
Bridge |
Intel
845E |
Intel
845G |
Intel
850E |
SiS
645DX |
SiS
648 |
VIA
P4X400 |
| AGP Controller | 4X |
4X
|
4X |
4X |
8X |
4X |
| Memory Controller | 64-bit
DDR266 |
64-bit
DDR333* |
32-bit
PC1066*** |
64-bit
DDR333 |
64-bit
DDR400** |
64-bit
DDR400 |
| Memory Bandwidth (Max) | 2.1GB/s |
2.7GB/s |
4.2GB/s |
2.7GB/s |
3.2GB/s |
3.2GB/s |
| FSB Interface | 400/533MHz |
400/533MHz
|
400/533MHz |
400/533MHz |
400/533MHz |
400/533MHz |
| South Bridge Link | HubLink |
HubLink
|
HubLink |
MuTIOL |
MuTIOL |
V-Link |
*DDR333 is unofficially supported by this chipset, official support will come with the 845GE and 845PE
**DDR400 is unofficially supported
***PC1066 is unofficially supported
The Most Feature filled South Bridge since nForce
The 648 North Bridge will be paired up with the new 963 South Bridge from SiS. The 963 is identical to the 962 South Bridge in its feature set, which includes dual ATA/133 IDE controllers, support for up to 6 USB 2.0 ports, integrated Ethernet MAC, AC’97 audio support and a 3-port IEEE-1394 (Firewire) controller. Only NVIDIA’s MCP-T can surpass the 963 in terms of features however, there won’t be any NVIDIA powered P4 chipsets anytime soon.
Just like SiS’ previous chipsets, the North and South Bridge are linked using their own Multithreaded I/O Link (MuTIOL) technology. MuTIOL is SiS’ answer to Intel’s Hub Architecture and VIA’s V-Link, a serial interconnect between the North and South Bridges.
The 963 South Bridge only differs from its predecessor in that the MuTIOL bandwidth has been increased from 533MB/s up to 1GB/s. The PCI, Firewire, USB and IDE devices running off of the 963 South Bridge won’t even come close to saturating the old 533MB/s link so the increase in MuTIOL bandwidth won’t be the cause of any noticeable performance boosts.
| South
Bridge |
Intel
845E |
Intel
845G |
Intel
850E |
SiS
645DX |
SiS
648 |
VIA
P4X400 |
| IDE Controller | ATA/100 |
ATA/100
|
ATA/100 |
ATA/133 |
ATA/133 |
ATA/133 |
| USB 2.0 Support | Y |
Y |
N |
N |
Y |
Y |
| Firewire Support | N |
N |
N |
N |
Y |
N |
| North Bridge Link Bandwidth | 266MB/s |
266MB/s |
266MB/s |
533MB/s |
1GB/s |
266MB/s |
The Reference Board
Although we were only able to get our hands on two motherboards based on the SiS 648 chipset, there is more support behind this chipset launch than any other previous SiS release. All of the major motherboard manufacturers are scheduled to produce 648 based solutions and will be shipping them before the end of July, with some trailing into August. While this isn’t the ideal case where a chipset launch is paired up with the launch of a handful of motherboards, this is definitely the best we’ve seen from SiS.
The first board we tested was the SiS 648 Reference board provided by SiS themselves. In SiS’ usual fashion, their reference board is built on a non-ATX form factor that is significantly larger to aid in debugging.
The second board that arrived in our hands based on the 648 chipset was Shuttle’s AS45. We will be providing an individual review of the Shuttle AS45 shortly but the board was worth mentioning here as it was ready by the launch of the chipset.
During our tests we didn’t encounter any stability issues with the reference board.
DDR400: Not Ready for Prime Time
The race to provide support for DDR400 is entirely marketing driven at this point, as many things are in this industry. Support from chipsets has been in place for quite some time; the SiS 648 unofficially supports the frequency, the P4X400 does and NVIDIA’s upcoming nForce2 does as well.
With the Pentium 4, DDR400 has the potential to offer a reasonable performance gain over DDR333 courtesy of the platform’s high-bandwidth FSB. However, the DDR400 modules that are currently available (not publicly) are of very low yield and don’t offer any real performance benefits over DDR333. This will change as yields improve and chipset manufacturers can tune their memory controllers for DDR400 operation, but that won’t realistically happen until well into 2003. The main limitation for DDR400 adoption at this point will be module availability and chip yield.
We ran through our tests with both DDR333 and DDR400 modules where possible, using a 256MB Twinmos module with CAS 2.5 Winbond chips for the DDR400 tests. There were only two platforms in this comparison that would work with DDR400: the SiS 648 and VIA’s P4X400. VIA’s P4X400 board did not run DDR400 as seamlessly as the SiS 648 reference board and was not able to produce scores in some tests; in other situations it merely crashed randomly.
The Test
We compared six different chipsets in this review, the motherboards we used to represent each chipset were:
Asus P4T533-C - Intel 850E
Asus P4B533-E - Intel 845E
SiS Reference Board - SiS 648
Soyo P4S 645DX Dragon - SiS 645DX
Shuttle P4X333 - VIA P4X333
VIA P4PB400 - VIA P4X400
| Windows
XP Professional Test Bed |
|
| Hardware
Configuration |
|
| CPU | Intel
Pentium 4 2.4GHz |
| Motherboard | Asus
P4T533-C - Intel 850E Asus P4B533-E - Intel 845E SiS Reference Board - SiS 648 Soyo P4S 645DX Dragon - SiS 645DX Shuttle P4X333 - VIA P4X333 VIA P4PB400 - VIA P4X400 |
| RAM | 2
x 128MB PC1066 Kingston RIMMs 1 x 256MB DDR333 Kingston DIMM 1 x 256 DDR400 Twinmos DIMM |
| Sound | None |
| Hard Drive | 120GB
Western Digital Special Edition 8MB Buffer |
| Video Cards (Drivers) | NVIDIA GeForce3 Ti 200 (64MB) - v29.42 |
Content Creation & General Usage Performance
SYSMark has become a solid measurement of overall system performance since its induction into our benchmarking suite. Although the Internet Content Creation suite caters to more of a niche market, the Office Productivity tests are a perfect measurement of overall system performance in the applications all of us use on a daily basis.
The applications benchmarked include:
· Internet Content Generation: Adobe Photoshop® 6.01, Adobe Premiere® 6.0, Microsoft Windows Media Encoder 7.1, Macromedia Dreamweaver 4, and Macromedia Flash 5
· Office Productivity: Microsoft Word 2002, Microsoft Excel 2002, Microsoft PowerPoint 2002, Microsoft Outlook 2002, Microsoft Access 2002, Netscape Communicator® 6.0, Dragon NaturallySpeaking Preferred v.5, WinZip 8.0, and McAfee VirusScan 5.13.
For more information on the methodology and exactly what SYSMark does to generate these performance scores check out BAPCo's SYSMark 2002 Whitepaper.
The P4X400 would not complete either of the SYSMark tests without consistently failing the suite due to timing errors; we're not sure if this is an issue with VIA or the benchmark although we have seen similar issues on other chipsets.
|
317
314
309The performance spread between the fastest 850E chipset and the slowest 845E solution is less than 10% meaning that the performance difference between these solutions is negligible. Because of the already small differences between the chipsets it's no surprise that the performance boost from moving to DDR400 isn't significant. It should be noted that we're comparing DDR333 with a CAS latency of 2.5 to DDR400 with a CAS latency of 2.5 as well, if we had used CAS2 DDR333 then the benchmark could have been tilted in favor of DDR333 as well.
This is testament to the fact that DDR400 won't be ready for prime time until much later this year or into 2003; right now chipset manufacturers are more concerned with optimizing DDR333 performance than tuning their solutions for DDR400.
|
There's a much larger performance spread in the Office Productivity suite, which is arguably more important than the Internet Content Creation results for the vast majority of users.
The SiS 648 is able to jump on the heels of Intel's 850E solution and even equal its performance with DDR400. Although not pictured here, the 845G with DDR333 offers performance in between the P4X333 and the SiS 648 solutions.
Quake III Arena Performance
Quake III's usefulness as a gaming benchmark has diminished mostly because of the fact that we're able to consistently produce frame rates over 300 fps at 1024x768 with the fastest video cards. But as the benchmark becomes less GPU limited, it becomes a perfect candidate for CPU and platform tests such as this one.
|
181.1When armed with DDR400, the SiS 648 chipset ends up being the fastest solution on the chart, even outperforming the 850E with PC1066 RDRAM. With DDR400 the performance boost is around 3% at this resolution over conventional DDR333. What's interesting to note is that the P4X400 is actually much faster with DDR333 than with DDR400, even when using the same timings but simply adjusting operating frequency the DDR400 is significantly outperformed on VIA's P4X400 board.
Unreal Tournament 2003 Performance - High Detail
We introduced the latest Unreal Tournament 2003 benchmark in our GPU Shootout article a few weeks back and we're continuing to use it as an example of a next-generation game test.
We benchmarked under two different levels and detail settings; the first was DM-Antalus with High Detail settings, an overly GPU bound benchmark, and the second was DM-Asbestos with Medium Detail settings.
|
As we just finished mentioning, the primary limitation here is the GPU and thus we don't see any tangible performance difference between the chipsets.
|
Increasing the resolution helps separate the chipsets a bit, with the 850E and SiS 648 taking the lead once again.
Unreal Tournament 2003 Performance - Medium Detail
|
When the GPU isn't providing the major limitation in the game the 850E has the potential to truly shine and its massive bandwidth advantage puts the rest of the solutions to shame. We're not exactly sure why there's such a large performance gap between the 850E with PC1066 and the rest of the contenders but it's definitely noticeable.
|
Cranking up the resolution changes the picture significantly; the 850E loses its massive lead and is constrained by the GPU, giving the VIA P4X400 the slight lead. The SiS 648 is in the top three but this time isn't the fastest of all of the contenders.
High End Workstation Performance - SPEC Viewperf 7.0
The latest version of SPEC Viewperf proves to be an excellent stress test for memory bandwidth and overall platform performance as you're about to see. The benchmarks included version 7 of the benchmark suite are:
3ds max (3dsmax-01)
Unigraphics (ugs-01)
Pro/Engineer (proe-01)
DesignReview (drv-08)
Data Explorer (dx-07)
Lightscape (light-05)
|
There's a significant separation between the 850E and the slowest performing 845E in this benchmark, with a performance gap of over 27%. Once again we have the 850E and SiS 648 at the top of the charts, with VIA's P4X333 and P4X400 falling slightly behind. Also note that the P4X400 with DDR400 is slower than the same setup with DDR333.
Seeing as how the P4X400 is essentially a rebadged P4X333 chipset, the close proximity of the two motherboards in this test is expected.
|
The standings don't change at all in the DesignReview test.
|
High End Workstation Performance - SPEC Viewperf 7.0 (continued)
The final set of SPEC Viewperf benchmarks conclude what we've been seeing thus far; the 850E and 648 are very close in performance, even when DDR333 is used.
|
|
|
Synthetic Memory Benchmarks
As a quick addition we decided to throw in results from PCMark 2002's memory test, we didn't report the scores that were tabulated to produce this final result but the numbers below are representative of the raw memory controller performance of the platforms we tested.
|
Final Words
Based on benchmarks of SiS' own reference board, the 648 seems like a very promising solution. The chipset almost always performed within a few percent of Intel's 850E and does so at a significantly lower cost; this explains why the 648 has the most initial support out of any SiS chipset we've seen.
The only thing that remains in order for us to pass final judgment on the chipset is to see more motherboards based on the solution. We already have a board from Shuttle in our hands and MSI is on their way to shipping us a 648 solution as well, but we'd like to see at least 8 or 9 boards based on the chipset in order to feel comfortable recommending it.
SiS has definitely come a long way in the past couple of years; from stealing VIA's thunder with the Socket-A 735 chipset to being the primary player in the 3rd party P4 chipset market, if they can improve their product execution SiS could easily become a force to be reckoned with.
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