Original Link: https://www.anandtech.com/show/1197
SiS755 Reference Board: Athlon64 from SiS
by Wesley Fink on November 23, 2003 11:19 PM EST- Posted in
- CPUs
The launch of Athlon 64 has brought us 2 chipsets thus far: the nVidia nForce3 150 and VIA K8T800. As we have discussed in reviews of boards based on these chipsets, neither one really meets the specifications that we would like to see in Athlon 64 chipsets.
While VIA performs at the specified 800 Hyper Transport speed, it is hampered by lack of a real means to fix AGP/PCI lock. This severely limits the ability of VIA chipset boards to overclock, and is the most important complaint we have had with this chipset. VIA is also a 2-chip solution and the actual communication speed between the North and South Bridge chips is specified as 500MHz, which is much slower than the 1.6GHz to 3.2GHz that is used for internal communication of the other components on HyperTransport. While VIA has made a lot of splash about being the “only” chipset to implement 800 HT speed, they are really telling only part of the story, since the slower North/South bridge communications are certainly a bottleneck if VIA is correct about the impact of a slower HT speed on other chipsets. You simply cannot have it both ways.
nVidia, on the other hand, fully implements the ability to fix the PCI/AGP on nForce3-150 chipset boards. However, current 150 version chipsets cannot run with stability any faster than 600 HyperTransport. The nForce3 does offset this limitation partially with their one-chip implementation of nForce3 150. This assures the single chip is communicating with other HT components at the fastest speeds available, and is not hampered by a slower North/South bridge bus.
The practical reality is these differences in the nForce3-150 and VIA K8T800 have been impossible to measure at stock performance speeds. With the Athlon 64 memory controller on the chip, it appears the chipset has less impact on final performance, and our benchmarks with the VIA and nF3 chipsets have been virtually identical. Overclocking, on the other hand, has been quite different between the 2 chipsets. Using the same Athlon64 chip, we have been able to reach overclocks to the 230 (920FSB) range with nF3-150; VIA solutions, conversely, have never been able to reach much beyond the 214-215 range due to problems of the floating PCI/AGP speeds.
nVidia will have a new chipset in the next few months that will run at 800 HT called the nForce3-250. VIA is also rumored to have a new chipset with PCI/AGP lock in the works. Frankly, we are more skeptical as to whether or not the VIA solution will appear, since VIA has never had a chipset with PCI/AGP lock. We also believe that VIA would have implemented PCI/AGP lock if it had been doable with their current core logic in the year we all waited for Athlon64 to appear. While there is promise of better solutions from both nVidia and VIA, the reality today is neither chipset does exactly what we want.
SiS is now releasing their Athlon64 solution, which we are evaluating in this look at the SiS755 chipset. SiS does run at 800 HyperTransport, and SiS also has implemented the ability to run the PCI/AGP speed asynchronously, so it is possible to fix PCI/AGP speed. On paper, at least, SiS appears to be a better Athlon64 solution than either nForce3-150 or VIA K8T800. While it is also a 2-chip solution like VIA, the SiS755 chipset provides North/South communication using the proprietary Mutiol bus. For the 755, SiS has increased Mutiol speed to 1GHz, a higher speed with less chance of saturating the bus than the VIA solution.
A Closer Look at SiS755
SiS755 is compatible with either Athlon64 or Opteron/Athlon64FX. The Reference Board is an Athlon64 board supporting Socket 754 A64 chips. Our reference board combined the 755 Northbridge with the 964 Southbridge, which adds many contemporary features.While the 755 can also be combined with the older 963L Southbridge — a combination you will see on cheaper solutions — the most competitive features are provided when the 964 is used. The 964 adds SATA RAID, increases USB ports to 8, and adds base code for “Hollywood Audio”-10/100 Ethernet-Modem.
SiS755 Specifications
- SiS Propriety Hyper Streaming Engine Architecture
- “Low Latency” with Single stream
- “Pipelining” and “Concurrent Execution” with Multiple streams
- “Prioritized Channel” with Specific stream
- “Smart flow control” and “Intelligent arbitration” with Smart stream
- Host Interface Controller
- Supports AMD Athlon 64/ Opteron CPUs
- 800/600/400/200 MHz Front-Side Bus
- HyperTransport Technology with 8/16 links support
- HyperTransport Technology up to 1600MT/s bandwidth
- Support AGP 8X Interface
- Support AGP 8X/4X Interface
- Support Enhancements of AGP v3.0 Register Format
- Support Fast Write Transaction
- MuTIOL 1G Delivering 1GB/s Bandwidth
- Proprietary Interconnect between SiS755 and SiS964
- Bi-Directional 16-bit Data Bus
SiS964 MuTIOL 1G® Media I/O
- MuTIOL 1G® Delivering 1GB/s Bandwidth
- Proprietary Interconnect between SiS755 and SiS964
- Bi-Directional 16-bit Data Bus
- USB 2.0/1.1 Host Controller
- One EHCI USB 2.0 Controller and three OHCI USB 1.1 Controllers
- Support Total 8 USB 2.0/1.1 Ports
- Support USB 2.0 High-Speed Device @480 Mb/s Transfer Rates
- Serial ATA Host Controller
- Two independent ports and flexible channel allocation
- Compliant with Serial ATA 1.0 Specification
- Support Ultra DMA 150
- Support RAID 0, RAID 1 and JBOD configuration
- PCI 2.3 Specification Compliance
- Support up to 6 PCI Masters
- Fast Ethernet/Home Networking Controller with MII Interface
- Support 10/100Mb Fast Ethernet or 1/10Mb HomePNA 2.0 with External PHY
- Audio/Modem Controllers with AC'97 Interface
- AC'97 v2.3 Compliant
- Support 6 Channels of AC'97 Speakers Out and v.90 HSP Modem
- Advanced Power Management
- ACPI 2.0 and APM 1.2 Compliant
- Dual IDE Channels with Parallel ATA 133/100/66
- LPC 1.1 Interface
- Integrated RTC
- Integrated Keyboard/PS2 Mouse Controller
SiS755 Reference Board: Basic Features
Motherboard Specifications | |
CPU Interface | Socket 754 Athlon64 |
Chipset | SiS755 / SiS964 |
Bus Speeds | 133 to 253 (in 1MHz increments) |
PCI/AGP Speeds | Synchronous or Asynchronous PCI/AGP FIX at 66/33, 75/37, or 80/40 |
Core Voltage | None available on Reference Board |
DRAM Voltage | None available on Reference Board |
AGP Voltage | None available on Reference Board |
HyperTransport Voltage | None available on Reference Board |
Memory Slots | Three 184-pin DDR DIMM Slots Single-Channel Configuration Regular Unbuffered Memory to 2GB Total |
Expansion Slots | 1 AGP 8X Slot 2 PCI Slots (up to 6 may be available) |
Onboard Serial ATA RAID | SiS964 (2 Drives, 0, 1) |
Onboard IDE | Two Standard ATA133/100/66 (4 drives) Up to 3 connectors/6 drives may be used |
Onboard USB 2.0/IEEE-1394 | 8 USB 2.0 ports supported by 964 No Firewire — Must use additional chip |
Onboard LAN | 10/100 Ethernet by 964 |
Onboard Modem | v.90 Modem |
Onboard Audio | AC '97 2.3 6-Channel supported by 964 Realtek ALC658 codec |
BIOS Revision | Reference Board |
In most cases, Reference Boards are quite different from the production boards that will later appear with the Reference Board chipset. While certain component arrangements may be retained from a Reference Board, we are evaluating a board designed for testing and qualification, and generally not for production. They are also normally designed to be tested on the bench, out of any case.
In the picture above, please ignore layout, but look instead at the features provided on the Reference Board. With SATA Raid, 8 USB 2.0/1.1 ports, ATA133 IDE, 10/100 Ethernet, v.90 Modem, and the higher level 2.3 AC'97, the SiS755/964 certainly compares favorably in features with the VIA K8T800. As with the VIA, SiS755 far outclasses the nForce3 in the features category, but we are told this will be corrected with the nF3-250. The only feature really missing from the 755/964 is Firewire, which must be implemented with a separate chip by the board manufacturer. Frankly, this is not a problem at all in our estimation. We also wish SiS had provided a real option for Gigabit LAN. While the current need for 1000Mb LAN is mostly hype, there is no doubt that this speed will catch on fast and make a real difference in performance in the future. With most broad-band connections still only requiring 10Mb speed, the option for 100Mb speeds seems adequate. However, many are already enjoying 1000 speeds between components on their home or Office LAN, and the usefullness of 1000Mb LAN capabilities will certainly increase quickly.
We are seeing the Realtek ALC658 audio codec used on many of the top boards that we have recently tested. The 658 is a significant improvement over the earlier Realtek AC97 codecs, and provides much higher quality performance:
“The ALC658 has six 20-bit DAC channels, two pairs of stereo 18-bit ADC, and an AC'97 2.3 compatible six-channel audio CODEC designed for PC multimedia systems. The ALC658 incorporates proprietary converter technology to achieve 100dB sound quality, meeting performance requirements on PC99/2001 systems and placing PC sound quality at the same level as consumer equipment.”More information on the features and specifications of ALC658 is available at Realtek
As seen on every Athlon64 and Athlon64 FX board we have tested, the SiS755 Reference Board uses both the 20-pin ATX power connector plus the 4-pin 12V power connector.
Three DIMM slots support up to 2 Gigabytes of standard unbuffered Single-Channel memory. Single-Channel is the only memory configuration available with any of the Athlon64 chips. We demonstrated in our launch articles on the Athlon64 and Athlon64FX processors that Dual-Channel memory provides only a small benefit on the A64 platform. The real performance difference between single and dual-channel memory is small on the Athlon64/Athlon64 FX and not comparable to the large performance differences that we see on the bandwidth-hungry Pentium 4. 1, 2 or 3 DIMMs can be installed.
SiS755 Reference Board: BIOS and Overclocking
AGP/PCI Lock and 800 HyperTransport
One of the biggest complaints with the VIA K8T800 is the absence of a PCI/AGP frequency lock. With the PCI/AGP frequency forced to float, overclocking becomes limited by the AGP card or PCI peripherals instead of the processor. System stability while overclocking is also compromised with synchronous AGP/PCI. SiS has implemented PCI/AGP lock on their recent chipsets, and it is also used on the SiS755. In addition, SiS runs the HyperTransport at a full 800MHz, instead of the lower speeds used on the nForce3-150 chipset. This combination of features makes the 755 the best Athlon64 chipset currently available, at least on paper.BIOS
Manufacturers will determine the BIOS used in production boards, but the BIOS used with the Reference Board influences the decision, since it is already a working BIOS. SiS uses the familiar Award BIOS in the 755 Reference board.
HyperTransport options, AGP, and Memory Timings are available in Advanced Chipset features. HT is running at 800MHz at default.
SiS has provided “word” options for DDR timings on recent chipsets. This is an option some end-users like, but it is generally criticized by enthusiasts, who prefer actual settings. SiS provides both options in their Reference 755 BIOS. As you can see, you can choose 6 levels of memory timings: Normal, Fast, Fast+, Fast++, Ultra, and Ultra+.
Or you can select “Manual” from the timing settings and set your own timings from a very large selection of memory timing options. Low-end versions of SiS755 boards will likely offer only the “Word” timings, but with full settings, mid- to high-end SiS boards will likely offer a full range of memory timing adjustments.
FSB Overclocking Results
Reference Boards are not really designed for overclocking, and there are no voltage adjustments available that we would see on boards with this option. However, with PCI/AGP lock available, we were anxious to see if the SiS755 did indeed perform better.Front Side Bus Overclocking Testbed Default Voltage |
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Processor: | Athlon64 3200+ 2.0GHz |
CPU Voltage: | 1.5V (default) |
Cooling: | AMD Stock Athlon64 Heatsink/Fan |
Power Supply: | Powmax 350W |
Maximum OC: | 2150MHz (+8%) 215FSB |
The above overclocking setup at default voltage allowed us to reach a stable Frequency of 215 at 800 HyperTransport with AGP/PCI fixed at 33/66. We really expected higher overclocks with the available PCI/AGP lock, but the potential for outstanding overclocking is at least there with the SiS755 chipset. By lowering the HT to 600 and slowing memory timings, overclocks in the low 220 range were reached, but nothing higher. At this point, we really need to see working boards from major manufacturers that specialize in overclocking to determine better the true overclocking capabilities of the 755 chipset. In overclocking, the 755 Reference Board with PCI/AGP fixed exhibited “either/or” performance. Either it booted (and if it did, it was stable no matter what was thrown at the board), or it did not boot, and it required a BIOS reset.
Reference Boards are rarely a good indication of the true overclocking abilities of a chipset because they are designed to qualify and demonstrate a chipset at design parameters. The features are here for the best overclocking in Athlon64 chipsets, but that has not yet been seen on the SiS755. Production boards should provide better answers to the overclocking questions.
SiS755 Reference Board: Stress Testing
We performed stress tests on the SiS755 Reference Board in these areas and configurations:1. Chipset and motherboard stress testing, conducted by running the FSB at 215MHz.
2. Memory stress testing, conducted by running RAM at 400MHz with 2 DIMM slots filled and at 400MHz with all 3 DIMM slots filled at the lowest memory timings possible.
Front Side Bus Stress Test Results:
As normally done in our testing of production motherboards, we ran a full range of stress tests and benchmarks on the SiS755 Reference Board to test stability at an overclocked speed. This included Prime95 torture tests, and the addition of other tasks — data compression, various DX8 and DX9 games, and apps like Word and Excel — while Prime95 was running in the background. Finally, we ran our benchmark suite, which includes ZD Winstone suite, Unreal Tournament 2003, SPECviewperf 7.0, and Gun Metal Benchmark 2. At default voltage, 215MHz was the highest overclock that we were able to achieve with the SiS755 at 800 HT while running these tests.Unlike our experiences with some of the VIA K8T800 overclock, the SiS was completely stable when it was able to run an overclock. The PCI/AGP lock, at the very least, appears to improve stability of the overclocked speed.
Memory Stress Test Results:
This memory stress test simply tests the ability of the SiS755 Reference Board to operate at its officially supported memory frequency (400MHz DDR) at the lowest supported memory timings that our Mushkin PC3500 Level 2 memory will support:Stable DDR400 Timings — 2 DIMMs (2/3 DIMMs populated) |
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Clock Speed: | 200MHz |
Timing Mode: | N/A |
CAS Latency: | 2.0 |
Bank Interleave: | N/A |
RAS to CAS Delay: | 2T |
RAS Precharge: | 6T |
Precharge Delay: | 2T |
Command Rate: | N/A |
We had no problem running 2 DS 512MB DIMMs of our standard Mushkin PC3500 Level2 in the SiS755 Reference Board. We were also able to run the memory test suite with complete stability at 2-2-2-6 timings. Tests with some demanding games other than our tests suite, however, required RAS-to-CAS to be slowed to 3 for most stable operation. We also tested the SiS755 with just one DIMM and found timing requirements for one or two DIMMs to be the same.
Filling all available memory banks is more strenuous on the memory subsystem than testing 2 DIMMs, and, unlike some experiences with other Athlon 64 chipsets, 3 DS DIMMs worked just fine on the SiS755. We did have to lower memory timings to 2-2-3-6 for stable operation with 3 DIMMs, but this is a very small decrease.
Stable DDR400 Timings — 3 DIMMs (3/3 DIMMs populated) |
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Clock Speed: | 200MHz |
Timing Mode: | N/A |
CAS Latency: | 2.0 |
Bank Interleave: | N/A |
RAS to CAS Delay: | 3T |
RAS Precharge: | 6T |
Precharge Delay: | 2T |
Command Rate: | N/A |
We tested the memory timings with both 2 and 3 banks filled using several stress tests and general applications to guarantee stability. Prime95 torture tests were successfully run at the timings listed in the above charts. We also ran ScienceMark (memory tests only) and Super Pi. None of the three stress tests created any stability problems for the SiS755 Reference Board at these memory timings.
While it was good to see the SiS able to run with 3 DS DIMMs installed, we did notice unusual latencies when testing with 3 DIMMs in ScienceMark 2.0. While performance was completely stable with 3 DIMMs, latency with 3 DIMMs is almost twice the latency with 2 DIMMs. Since the latency numbers with the SiS had been quite good in tests, we looked a little deeper into what was going on here. Interestingly, latencies tested virtually the same with either one or two DS DIMMs installed. However, once a 3rd DIMM was added, whether single- or double-sided, the latency and memory bandwidth dropped to about half the values with 1 or 2 DIMMs. This may be an issue with just the SiS755 Reference board, and we plan to look at this further on production boards. For now, up to 4 sides (2 DS DIMMs) could be used with top performance. Using 5 or 6 sides (3 DS DIMMs or 2 DS and a single-sided) increased latency significantly. Our advice, until we can test this further on production boards, is to limit memory to 4 sides for best performance with the SiS755.
Performance Test Configuration
Performance Test Configuration | |
Processor(s): | AMD Athlon64 3200+ (2.0GHz) AMD Athlon64 FX51 (2.2GHz) AMD Athlon XP 3200+ (2.2GHz, 400MHz FSB) Intel Pentium 4 at 3.2GHz (800FSB) |
RAM: | 2 x 512MB Mushkin PC3500 Level II 2 x 512MB Mushkin ECC Registered PC3200 |
Hard Drive(s): | Maxtor 120GB 7200 RPM (8Mb Buffer) Seagate 120GB 7200RPM SATA (8Mb buffer) |
Video AGP & IDE Bus Master Drivers: | SiS 1.17a AGP/IDE 2.04/RAID 1.03 VIA 4in1 Hyperion 4.49 (August 20, 2003) NVIDIA nForce version 2.45 (7/29/2003) |
Video Card(s): | ATI Radeon 9800 PRO 128MB (AGP 8X) |
Video Drivers: | ATI Catalyst 3.8 |
Operating System(s): | Windows XP Professional SP1 |
Motherboards: | SiS755 Reference Board Abit KV8-MAX3 @ 204.3FSB Gigabyte K8NNXP-940 Athlon64 FX51 ChaintechZNF3-150 (nForce3) Athlon64 3200+ MSI K8T Neo (VIA K8T800) Athlon64 3200+ DFI NFII Ultra (nForce2 U400) Barton 3200+ Asus P4C800-E (Intel 875P) 3.2Ghz P4 |
The Athlon64 FX requires Registered or Registered ECC memory. Tests with the Gigabyte K8NNXP-940 were therefore performed with Mushkin High Performance Registered ECC DDR400 memory. Recent performance tests on Athlon64, nForce2 Ultra 400 and Intel 875/865 boards used 2 x 512MB Mushkin PC3500 Level II Double-bank memory.
All performance tests were run with the ATI 9800 PRO 128MB video card with AGP Aperture set to 128MB with Fast Write enabled. Resolution in all benchmarks is 1024x768x32.
For the fairest comparisons, benchmarks were recompiled for the Asus P4C800-E using a 3.2GHz Pentium4 processor.
Additions to Performance Tests
We have standardized on ZD Labs Multimedia Content Creation Winstone 2003 and ZD Labs Business Winstone 2002 for system benchmarking. Science Mark 2 Memory Performance, 9/23/03 update, was included to compare Memory Bandwidth and Latency of the Athlon64, Athlon64 FX51, and Pentium 4 3.2GHz.Game Benchmarks
We have added Aquamark 3 and Gun Metal DirectX Benchmark 2 for Direct X 9 from Yeti Labs, and X2 Benchmark, which includes Transform and Lighting effects, to our standard game benchmarks. In the near future, we will be adding other benchmarks from the AnandTech Video Card Game Suite.Content Creation, General Usage and Memory Performance
The SiS755 Reference Board performs as well as any Athlon64 board that we have tested in Content Creation. In General Usage, it is surprisingly the equal of the heavily-tweaked Abit K8V-Max3 and performs at about the same level as the Gigabyte FX51 board. This is really outstanding performance and we look forward to seeing production boards based on the SiS755 chipset.
Science Mark 2 was recently updated, and we used the latest 9/23/03 build for our Memory benchmarking. With the memory controller on the Athlon64 processor, we really expected memory performance among Athlon64 chipsets to be about the same. The SiS755 was a pleasant surprise in posting the lowest latency figures that we have yet seen on an Athlon64 chipset. SiS755 was also a bit faster than VIA K8T800 in ScienceMark memory bandwidth, making it the fastest Athlon 64 chipset so far. The performance differences, however, are small, and are most likely explained by the 2-2-2-6 memory timings supported on the SiS chipset compared to the 2-2-3-6 timings that were required on VIA's offering at DDR400.
Media Encoding and Gaming Performance
The Gaming performance of the SiS755 Reference Board equals or tops the best that we have seen so far on an Athlon64 chipset. SiS has been hampered in the past with AGP driver issues, which have impacted their scores on video-intensive benchmarks. Gaming scores certainly indicate that the new 755 chipset combined with 1.17a AGP drivers are a huge improvement and comparable to the best video performance we have seen.
Quake 3, Unreal Tournament 2003, and Gunmetal 2 are the highest scores that we have seen on an Athlon64 board at stock speeds. Other test results are in the same range of the top Athlon64 scores for that test. All-in-all, we have to consider the SiS755 Reference Board an outstanding performer in game benchmarks.
High End Workstation Performance
Again, on SPECviewperf Workstation benchmarks, the SiS755, in general, produced the best scores seen on Athlon64 motherboards tests. In 5 of the 6 tests, the SiS755 is the best performing Athlon64 motherboard. While the FX51 is still the top AMD performer in most of the tests, SiS755 is very close or a better performer in several of the SPECviewperf benchmarks. This outstanding performance in SPECviewperf is another indication that SiS AGP drivers are now mature and competitive with solutions from other chipset vendors.
Final Words
When SiS asked if AnandTech would like to take a look at the SiS755 Reference Board, we really didn't know what to expect with the new SiS Athlon64 chipset. While past SiS chipsets for Pentium 4 had been outstanding performers and past Athlon chipsets had been innovative, there are few current SiS chipsets that seem to have everything to make them top performers. After looking more closely at the features of the 755, there was a little more excitement. On paper, the SiS755 is the first Athlon64 chipset to combine the ability to fix the AGP/PCI frequency with a full implementation of the 800MHz HyperTransport bus. In addition, while using a traditional North/South bridge chipset, SiS uses a 1GHz Mutiol bus between the chips to minimize the North/South bus as a potential bottleneck. The features of the 964 Southbridge are also fully competitive with SATA RAID, ATA133 IDE, 8USB 2.0 ports, integrated 100db Signal-to-Noise 5.1 channel audio, and 10/100 Ethernet. The only things that we might wish for are 100/1000 Ethernet and Firewire, both of which can be added by board manufacturers. On paper, at least, SiS755 appeared to be the best of current Athlon64 chipsets.Features are one thing, but there is more to high-performance computing that a feature check list. To our surprise, SiS755 also provided the best performance in AnandTech benchmarks of any Athlon64 chipset that we have tested. This applies across the benchmarks, and there does not appear to be a weak area in the performance of the SiS755 Reference Board. Memory Latency is the best we have seen, Content Creation and General Usage are competitive with the best we've seen on A64, gaming sets new highs for A64 performance, and SPECviewperf performance is the best we have seen on an Athlon64. The margin over other Athlon64 chipset boards we have tested is generally small, but it is consistent. SiS755 provides the best performance of any Athlon64 chipset that we have tested, and we are looking forward to evaluating production boards based on the SiS755.
Just before publishing our SiS755 review, SiS announced the new 755FX chipset. Unlike past SiS chipset naming, the 755FX is not designed to replace 755. 755 is a chipset for Athlon64 and Opteron, though we have yet to see plans for an Opteron board based on 755. 755FX is a chipset for the upcoming Socket 939 Athlon64FX, which will run Dual-Channel memory and can use standard unbuffered DDR memory that you probably already own. As the first announced Socket 939 chipset, we were also surprised to see SiS list a 1000MHz HyperTransport bus as one of the 755FX features. It certainly would appear, based on this announcement, that SiS is having no problem manufacturing high-speed low-noise HyperTransport, which only promises further improvement in the stability and overclocking capabilities of the 755 chipset in the future.
Overclocking tests with the SiS755 Reference Board were the only area that was mildly disappointing. The overclocks we achieved were pretty average, and we expected better from a board that provides AGP/PCI frequency lock. As stated in the review, conclusions about overclocking capabilities of a chipset should never be made with a Reference Board, so this area remains inconclusive until we can run benchmarks on production boards. SiS certainly does provide the features to allow the best overclocking yet seen on an Athlon64, but this needs to be confirmed with real hardware.
We recently saw a production mid-range SiS755 board at Comdex produced by ECS. That board is on the way to our labs, and we look forward to performance testing. We are also hoping to see SiS755 boards soon from manufacturers that are famous for overclocking capabilities like Abit, DFI, Asus, and Gigabyte.
To our surprise, the SiS755 Reference Board is the best-performing Athlon64 chipset that we have tested. AnandTech is therefore pleased to award the SiS755 our Gold Editor's Choice as the best Athlon64 chipset. With 800MHz HyperTransport, the option to fix the AGP/PCI frequency, the ability to run DDR400 at the fastest 2-2-2-6 timings, and a full range of memory timing adjustments, the SiS755 is the only Athlon64 chipset that is not missing one or more of these features. When combined with the 964 Southbridge providing SATA RAID, ATA133, and 8 USB 2.0 ports, it is easily the best Athlon64 chipset that we have seen. Until we see the upcoming nForce3-250 and the rumored update to VIA K8T800, the SiS755 is the best Athlon64 chipset that we have tested. |