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SiS748 Performance Preview June 06, 2003 Brandon Bell |
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Summary: In an attempt to capture more of the Socket A market, SiS is preparing its SiS748 chipset. Its 400MHz bus supports AMD's latest Athlon XP 3200+ processor and DDR400 memory. But does it have enough to compete with NVIDIA's nForce2? Read on to find out!
 Introduction | Page:: ( 1 / 14 ) |
If there were one thing the AMD platform has been missing lately many would agree that keyword would be competition. Among gamers and enthusiasts, there’s really only been one clear choice: NVIDIA’s nForce2 chipset. Since its debut at the end of last year, the nForce2 chipset has been winning the hearts and minds of AMD owners for its unique combination of features and outstanding performance. Even AMD realizes this -- their last three processor launches have all involved the nForce2 platform.
As a result, the biggest decision an AMD user has faced the past seven months hasn’t been debating over which chipset to build their system around, but which nForce2 motherboard to purchase. The competition hasn’t been sitting on their laurels however.
VIA has been tweaking, and then re-tweaking its KT400A chipset. We were originally told by motherboard manufacturers to expect the first crop of KT400A boards in late December ’02. Then when December came, we were told February. Of course, by the time February hit we were no longer asking about KT400A, in fact we were asking all the manufacturers without nForce2 boards why they didn’t have an nForce2 board! (It was all rather comical actually.)
By the time we received our first retail KT400A board it was April and AMD’s Athlon XP 3200+ with 400MHz bus was right around the corner. Performance of the chipset was good, but not great. VIA had improved its performance over KT400, but still fell short of the mark NVIDIA had set with nForce2 months ago. But the worst part of it all was the fact that KT600 was just months away, making the situation similar to the KT266-becomes-KT266A debacle all over again.
SiS hasn’t fared much better than VIA as of late. Since their 735 chipset took the Socket A world by storm a few years ago, a lot of their focus has shifted to their chipsets for the Pentium 4 platform. Up until VIA was granted a Pentium 4 bus license, SiS was the only real alternative to Intel’s core-logic; in fact they beat Intel to market with DDR memory support and have rapidly adopted the latest technologies.
On the Socket A platform their SiS735 follow-up, SiS745, was actually adopted by a wider number of motherboard manufacturers, making it in some ways a better success than 735, but it was always regarded as a value product.
SiS746 and SiS746FX suffered a similar fate, only motherboards based on these chipsets were only offered for the extreme value market. We’re talking ECS and ASRock boards here folks.
SiS has one last chance to capture market share in the Socket A market before AMD moves to Athlon 64 later this year. Their entrant? SiS748. Read on to see how it stacks up to the competition!
SIDEBAR: SiS748 Product Webpage
| North Bridge | Page:: ( 2 / 14 ) |
Since launching the SiS735 chipset, SiS has been taking incremental steps on the Athlon platform. SiS745 mainly added FireWire and DDR333 memory support to the 735 chipset, while SiS746 added AGP 8X to the mix. When AMD introduced its 333MHz bus last year SiS had to go back to the drawing board again, hence, SiS746FX was born. SiS746FX also brought DDR400 memory support, but as we learned with nForce2 last year, the Athlon XP platform performs best when both the memory bus and system bus operate at the same clock frequency.
Memory/system bus
This brings us to the SiS748 chipset. As you’ve probably guessed by now, its primary addition is support for AMD’s latest front side bus speed, 400MHz. This boosts peak bandwidth from 2.7GB/sec to 3.2GB/sec, increasing system performance. Like SiS’ previous chipset offerings, the memory bus and system bus can operate asynchronously or synchronously. At 400MHz, memory ratios of 1:1 and 6:5 (for DDR333 memory support) are offered, while at 333MHz system bus, ratios of 1:1, 5:6 (DDR400), and 5:4 (DDR266) are available.
In fact, SiS also provides all the memory ratios for AMD’s older 200MHz and 266MHz processors. This gives end users lots of flexibility. If you want to run your brand new Athlon XP 3200+ with older DDR333 memory, the SiS748 chipset allows that. OEMs love this feature as well, they can use this capability to pair one of AMD’s newer “Barton” Athlon XP processors with older DDR266 memory. The processor will grab the prospective customer’s attention, while he overlooks the slower memory the system ships with.
Memory controller
The memory controller itself supports up to 3GB of memory, with up to 3 memory sockets supported in DDR200/266/333 mode. This brings total support to 1GB per DIMM. Due to the higher frequency of DDR400 however, the maximum number of DIMMs supported drops to two (for up to 2GB of memory). This falls short of KT600, which supports up to 4GB of memory and nForce2, which also supports up to 3GB of RAM, but with all three DIMM sockets available in DDR400 mode.
Rounding out the feature set of the SiS748 North Bridge is its AGP 8X interface. There isn’t much new to say here other than the fact that we have yet to find a single application that takes advantage of this new graphics interface.
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One interesting aspect that we’ve found in all of SiS’ recent discrete chipsets is the lack of a heatsink on the North Bridge chip. This is largely accomplished due to the 0.18-micron manufacturing process it’s produced on.
With the higher bus speed this chipset supports you’d expect it would need some form of cooling, especially under load. However, SiS must not feel the same way. We conducted quick finger tests at random intervals during our testing and found that the SiS748 chip does indeed get fairly hot, unlike earlier chips, which barely got warm to the touch. The lack of a North Bridge heatsink means lower production cost to prospective motherboard manufacturers, but we’d rather see it implemented in final products.
SIDEBAR: SiS has also announced its Hammer chipset, SiS755
| SiS963L South Bridge | Page:: ( 3 / 14 ) |
MuTIOL
Like SiS’ previous chipsets, the North Bridge and South Bridge of the SiS 748 chipset are connected by SiS’ proprietary MuTIOL interconnect technology. MuTIOL acts as a pathway between both chips, is 16 bits wide, and operates at 533MHz. The link between both chips is bi-directional, meaning two independent pathways are used. One can be sending data from the SiS748 North Bridge chip to the SiS963L South Bridge, while the second can send data in the opposite direction.
The net result is that bandwidth between the two chips is 1GB/sec, the highest in the industry. SiS proclaims that with USB 2.0 peaking at 480MB/sec, IDE at 133MB/sec, and PCI at 133MB/sec, their MuTIOL interconnect is necessary to provide more effective bandwidth for these devices than competing solutions, offering better overall system performance under load. Keep in mind however, that these are peak figures on paper; in practice these devices won’t achieve their maximum effectiveness.
Features
The 963L South Bridge is an updated variant of what is nearly two-year-old technology. As a result, its feature set is beginning to show signs of age. For instance, 963L offers no native Serial ATA hard drive support. If a motherboard manufacturer chooses to implement a design with Serial ATA support, they must use the SiS180 companion chip. SiS180 supports up to two Serial ATA ports as well as one parallel ATA (with two devices configured in a master/slave configuration) allowing for up to eight devices when paired with the 963L.
In addition, SiS180 offers native IDE RAID support. According to SiS’ documentation, RAID Levels 0, 1, 0+1, and JBOD (spanning, combining two or more hard disks into one volume that is recognized by the OS; combining the capacity of both drives) are supported, making it more flexible than Intel’s recently released ICH5R.
Without native Serial ATA support, SiS963L falls short of VIA’s KT600 chipset, whose VT8237 South Bridge offers similar functionality built-in. NVIDIA’s nForce2 chipset also lacks Serial ATA support, although NVIDIA does plan to address this later this summer.
For connectivity, up to six USB 2.0/1.1 ports are supported (compared to six in nForce2 and eight in KT600) but since SiS has removed FireWire support from 963L, the SiS 748 chipset doesn’t support FireWire devices (a feature which is also omitted on other recent Athlon XP chipsets). Soft audio (5.1 channel) and modem are supported, as is 10/100 Ethernet.
SIDEBAR: SiS748 is the sixth chipset SiS has released for the Socket A platform.
| Testing impressions | Page:: ( 4 / 14 ) |
Since we’re dealing with a reference board here, we won’t discuss traits like the board’s layout and BIOS implementation. Motherboard manufacturers rather than SiS will decide both of these aspects. We have however provided a few pictures, as we know you enjoy looking at them.
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Stability
To test stability, we decided to push the specs of the hardware as much as we could. That means in DDR400 mode we conducted our testing with both memory sockets populated with 2-2-2 timings. Unfortunately we don’t have 1GB DIMMs available so we were unable to hit the max memory ceiling of the SiS 748 chipset.
In any case, stability of the reference SiS 748 platform was good but not perfect. The system locked up on three occasions over the course of our use with it. We have a suspicion that the temperature of the North Bridge compromised system stability. On one of those three instances textures on the screen were corrupted just before we lost the system, a characteristic you normally see during overclocking or when your system is overheating. Remember as we mentioned earlier in this article, the 748 North Bridge would get hot during extended testing. We didn’t encounter any application crashes or Windows blue screens, which is definitely a good sign.
Compatibility
If you recall our RADEON 9700 PRO reviews from last year, we were never truly able to give a thumbs-up to the SiS 648/RADEON 9700 combination. System stability just wasn’t where we thought it needed to be.
Therefore, one of the first cards we tested the SiS 748 reference boards with was the ATI RADEON 9700 PRO. We threw everything we could at it and didn’t encounter any problems. In fact, the entire RADEON 9x00 family of graphics cards worked perfectly, other than the aforementioned lockups.
Next, we tried GeForce FX 5900 Ultra. Once again we didn’t encounter anything nearly reminiscent of the SiS 648/RADEON 9700 problems we've encountered in the past. It looks like SiS has got their game together on the video front for SiS 748.
Likewise memory compatibility was flawless, although we do have to admit that we only have memory modules from Corsair, Mushkin, and OCZ to test with. We tested with their DDR333 and up DIMMs, so we’re talking high quality memory here.
Overall we were quite pleased to see the components we tested with work so flawlessly with SiS 748. We were definitely concerned about GeForce FX 5900 compatibility in particular since it is the newest card we have available.
SIDEBAR: We’re really curious to see SiS R659 chipset, the R658 chipset arrived too late with mediocre performance, but if SiS can deliver on time with R659 it may be a fairly interesting product.
| System Setup | Page:: ( 5 / 14 ) |
System Setup
AMD Athlon XP 3200+
ASUS A7N8X Deluxe 2.0 nForce2 Ultra 400 Motherboard
SiS 748 Reference Motherboard
512MB Corsair XMS3200 CAS2 Memory
ATI RADEON 9800 Pro 128MB
Catalyst 3.4
120GB IBM Deskstar DTLA 307030 ATA/100 Hard Drive
Windows XP Professional with Service Pack 1
DirectX 9
Desktop resolution 1024x768, 32-bit color, 75Hz refresh
Benchmarks
Unreal Tournament 2003 3D Mark 2003
Quake III: Arena version 1.17 ‘Demo001’ demo
Serious Sam: The Second Encounter – 32-bit color, Elephant Atrium demo
Comanche 4
Jedi Knight II
Splinter Cell
SIDEBAR: The SiS reference board had a pretty robust BIOS.
| 3D Mark 2003 | Page:: ( 6 / 14 ) |
3DMark03
SIDEBAR: SiS also recently announced it SiS648FX chipset for Pentium 4.
| 3D Mark 2003 – Frame Rates | Page:: ( 7 / 14 ) |
3DMark03 – Wings of Fury
3DMark03 – Battle of Proxycon
3DMark03 – Troll’s Lair
3DMark03 – Mother Nature
SIDEBAR: SiS was founded in 1987.
| Serious Sam SE | Page:: ( 8 / 14 ) |
Serious Sam SE (Elephant Atrium) – OpenGL
SIDEBAR: Unlike VIA, SiS actually has its own manufacturing facility.
| Quake III: Arena | Page:: ( 9 / 14 ) |
Quake III v.1.17 Demo001 – OpenGL
SIDEBAR: SiS is still working on its system-on-a-chip products.
| Comanche 4 | Page:: ( 10 / 14 ) |
Comanche 4 – DirectX 8
SIDEBAR: Besides chipsets, SiS also manufactures graphics cards.
| Unreal Tournament 2003 | Page:: ( 11 / 14 ) |
Unreal Tournament 2003 Flyby – DirectX 8
Unreal Tournament 2003 Botmatch – DirectX 8
SIDEBAR: SiS provides a list of supported memory they have tested with their chipsets.
| Splinter Cell | Page:: ( 12 / 14 ) |
Splinter Cell – DirectX 8
SIDEBAR: We’re still waiting on SiS’ DX9 part, Xabre II.
| Jedi Knight II | Page:: ( 13 / 14 ) |
Jedi Knight II - OpenGL
SIDEBAR: SiS was granted an RDRAM license from Rambus in Nov. 2001.
| Conclusion | Page:: ( 14 / 14 ) |
Right now you’re probably disappointed with the SiS748 chipset if you’re a hardware enthusiast. Performance is a little slower with the nForce2 Ultra 400 in single-channel mode, suggesting that it won’t be able to keep pace with NVIDIA’s nForce2 400 chipset. Likewise, the 2GB memory limitation with 2 DIMM sockets maximum really puts a crimp on your memory expansion options.
Making matters even worse is VIA’s KT600 chipset. We all know how staunchly VIA defends its Socket A territory by now. When the original nForce chipset was released, they quickly countered with KT333. nForce was quickly forgotten. For nForce2, everyone expected VIA to come back with some type of alternative, but as we saw with KT400A, it was stillborn and lacked the features needed to compete with nForce2. Now that VIA appear to be back with KT600, it appears that they won’t be able to take on nForce2 Ultra 400. Every motherboard manufacturer we’ve talked to refers to NVIDIA’s chipset as their flagship offering. Instead, KT600 will be paired squarely against SiS748.
With built-in Serial ATA and 4GB memory support, KT600 has a few compelling features SiS doesn’t natively offer. But at the same time, SiS doesn’t have the stigma attached to its name that VIA still does. Lets face it, we all know someone who’s run into problems with one VIA chipset or another.
So far, it looks like SiS will gain some traction with SiS748. We’ve been told that motherboards from AOpen, ASRock, Biostar, DFI, ECS, Iwill, Jetway, and MSI are in the works, with volume production of these boards beginning at the end of this month. From what we can tell however these will all be value products, with KT600 filling the mainstream and nForce2 Ultra 400 at the high-end.
We find it incredibly surprising that no one we’re aware of has announced an nForce2 400 motherboard. With the NVIDIA brand being popular among gamers, we’d naturally assumed motherboard manufacturers would be all over this chipset. When you consider the performance of the single-channel nForce2 Ultra 400 board, it seems like all a manufacturer would have to do is slap an NVIDIA logo on the nForce2 400 box and sell it a dirt-cheap price.
In any case, the SiS748 chipset offers good performance and a solid, yet somewhat mundane feature set. If SiS and motherboard manufacturers are able to get the price just right, a SiS748 motherboard could be the perfect platform for those of you looking to build a system on the cheap.
SIDEBAR: Which Socket A chipset is your motherboard based on? Would you consider SiS748 for your next PC? Voice your thoughts in the news comments!