ATI’s Crossfire: Best Overclocker on the Market?
by Wesley Fink on September 27, 2005 12:05 AM EST- Posted in
- CPUs
TRas and Memory Stress Testing
Memory tRAS Recommendations
In past reviews, memory bandwidth tests established that a tRAS setting of 11 or 12 was generally best for nForce2, a tRAS of 10 was optimal for the nForce3 chipset, and a tRAS of 7 was optimal for the nForce4 chipset. The recently tested ULi 1695 was best at tRAS of 10.
In our first review of the AMD chipset in Sapphire PURE Innovation - ATI's Chipset for the AMD Enthusiast, we established that the optimum tRAS setting for the AMD chipset is 7 to 8. We therefore used a tRAS setting of 7 for all ATI Crossfire AMD testing.
Memory Stress Test
Our memory stress test measures the ability of the Crossfire ATI to operate at its officially supported memory frequency (400MHz DDR), at the lowest memory timings that OCZ PC3200 Platinum Rev. 2 modules will support. All DIMMs used for stress testing were 512MB double-sided (or double-bank) memory. To make sure that memory performed properly in Dual-Channel mode, memory was only tested using either one dual-channel (2 DIMMs) or 2 dual-channels (4 DIMMs).
By using two DIMMs in Dual-Channel 128-bit mode, the memory performed in all benchmarks at the fastest 2-2-2-7 timings at default voltage.
Tests with all four DIMM slots populated on the ATI required a 2T Command Rate with 4 DIMMs in two dual channels. This is the pattern seen on other top-performing Socket 939 boards with all current AMD chipset families. The Crossfire AMD had no problem running at a 200 CPU speed setting with 4 double-sided DIMMs. Since the Athlon 64 memory controller is on the processor, there were no real surprises in the memory stress tests. The ATI Crossfire AMD is certainly competitive with the best Socket 939 boards in memory performance.
Memory tRAS Recommendations
In past reviews, memory bandwidth tests established that a tRAS setting of 11 or 12 was generally best for nForce2, a tRAS of 10 was optimal for the nForce3 chipset, and a tRAS of 7 was optimal for the nForce4 chipset. The recently tested ULi 1695 was best at tRAS of 10.
In our first review of the AMD chipset in Sapphire PURE Innovation - ATI's Chipset for the AMD Enthusiast, we established that the optimum tRAS setting for the AMD chipset is 7 to 8. We therefore used a tRAS setting of 7 for all ATI Crossfire AMD testing.
Memory Stress Test
Our memory stress test measures the ability of the Crossfire ATI to operate at its officially supported memory frequency (400MHz DDR), at the lowest memory timings that OCZ PC3200 Platinum Rev. 2 modules will support. All DIMMs used for stress testing were 512MB double-sided (or double-bank) memory. To make sure that memory performed properly in Dual-Channel mode, memory was only tested using either one dual-channel (2 DIMMs) or 2 dual-channels (4 DIMMs).
| Stable DDR400 Timings - One Dual-Channel (2/4 DIMMs populated) |
|
| Clock Speed: | 200MHz |
| CAS Latency: | 2 |
| RAS to CAS Delay: | 2T |
| RAS Precharge: | 7T |
| Precharge Delay: | 2T |
| Command Rate: | 1T |
By using two DIMMs in Dual-Channel 128-bit mode, the memory performed in all benchmarks at the fastest 2-2-2-7 timings at default voltage.
| Stable DDR400 Timings - 4 DIMMs (4/4 DIMMs populated) |
|
| Clock Speed: | 200MHz |
| CAS Latency: | 2.0 |
| RAS to CAS Delay: | 2T |
| RAS Precharge: | 7T |
| Precharge Delay: | 2T |
| Command Rate: | 2T |
Tests with all four DIMM slots populated on the ATI required a 2T Command Rate with 4 DIMMs in two dual channels. This is the pattern seen on other top-performing Socket 939 boards with all current AMD chipset families. The Crossfire AMD had no problem running at a 200 CPU speed setting with 4 double-sided DIMMs. Since the Athlon 64 memory controller is on the processor, there were no real surprises in the memory stress tests. The ATI Crossfire AMD is certainly competitive with the best Socket 939 boards in memory performance.
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ShadowVlican - Tuesday, September 27, 2005 - link
well i hope i can buy the Xpress200.... ATi ain't real until i can buy their motherboards readily everywhere i go (like nVidia's NF4)Beenthere - Tuesday, September 27, 2005 - link
It's no secret ATI has the ability to produce equal or better chipsets and GPUs than Nvidia - they have done this before. What ATI needs to do is get their sh*t together on the details and CUSTOMER SERVICE - Yeah, they've heard of it but evidently they don't know the MEANING OF IT ! Nvidia ain't much better, but ATI's so called Customer Support is a bad joke. Delivering what you promise is a VERY IMPORTANT CONSIDERATION when you are charging the enthusists market segment El PREMO PRICES for your hardware and you had better DELIVER THE GOODS. ATI has failed miserably and Nvidia ain't far behind despite the fact both companies have reaped fortunes from the consumer enthusiast market. Until both companies improve their CUSTOMER SUPPORT neither are getting any of our corporate dollars.yacoub - Tuesday, September 27, 2005 - link
Okay so the first good vendor (Asus or similar) to come out with a passively-cooled northbridge, the ALC-880"D" audio chip, a Southbridge with better USB performance, and the rest (it can even be a single GPU board so it's under or around $100 in price) gets my money. =Pyacoub - Tuesday, September 27, 2005 - link
Okay that wasn't supposed to reply to your post. Interesting.Live - Tuesday, September 27, 2005 - link
Does ATI crossfire support NCQ hard drives or not? Have I understood it correctly in that it is not supported trough the 4 SATA ports from the Southbridge but you can get support from the 2 ports from the included Sil controller?I have read the http://www.anandtech.com/storage/showdoc.aspx?i=24...">What's in a name? SATA II Misconceptions
But I still fail to get the facts straight. Does a SATA 2 controller, either from a SB or separate like the Sli, support all of the capabilities in the SATA 2 specs as long as the hard drive does so?
Since I plan on going dual core next, no NCQ seems like a deal breaker to me.
Wesley Fink - Tuesday, September 27, 2005 - link
The SB450 Southbridge does not support NCQ. The ULi M1573, used on the retail Gigabyte Crossfire AMD and some upcoming retail boards, DOES support NCQ. The Silicon Image 3132 on the ATI Reference Board supports both NCQ and 3Gb SATA2 on the extra SATA ports.The just introduced ULi M1575 Southbridge, which can be used with the ATI Crossfire Northbridge (as soon as it hits the market) supports 3Gb SATA2, NCQ, PCIe Gigabit Ethernet, Azalia HD audio, and features competitive USB throughput. The ATI SB600 will also implement all these features.
etriky - Tuesday, September 27, 2005 - link
Anyone have some links to shed some light on this quote."There is a lot of discussion on the web these days claiming that you can minimize the impact of the 2T setting with certain options on Revision E AMD processors."
I've done some searches and come up with nothing.
Thanks.
bigtoe36 - Tuesday, September 27, 2005 - link
forcing a burst length of 8 and forcing burst2opt can bring back some of the lost performance going to 2T, both these features are on the crossfire reference board.Also, i mamaged to talk DFI into making a direct copy of the ATI reference that will run reference bios files, we should see this board in October. This board will be released along side the board already designed by Oskar...so you will have the choice of 2 CF boards from DFI.
Palek - Tuesday, September 27, 2005 - link
On page 1, 2nd paragraph the article says:"AMD had done a particularly excellent job targeting the enthusiast for the new chipset launch, but that realization seemed to come late in the chipset development process."
I suspect that AMD should be ATI.
On page 3, 1st paragraph:
"AMD Crossfire" first, then "Crossfire AMD" later. "ATI Crossfire" or "ATI Crossfire AMD" may be less confusing.
Also on page 3, in last paragraph "AMD Reference Board" is used twice, but the board is referred to earlier on in the article as the "ATI Crossfire AMD Reference Board". "AMD Reference Board" makes it sound like AMD made it.
Question:
How hot did the northbridge get during various phases of your testing? I think a lot of users would appreciate some info regarding operational temperatures. If the ATI chipset turns out to run a lot cooler than nForce4 chipsets, I will gladly forgive the USB speed problems and go with an easier to cool motherboard.
Wesley Fink - Tuesday, September 27, 2005 - link
Corrected.See other comments for NB heat and cooling. My subjective observation is the ATI Northbridge is cooler during heavy OC than the nF4 under the same conditions. However, many of you push boards a lot further than I do so you can take that with a grain of salt. ATI designed this board for the enthusiast and extrene overclocking and temperature under stress was a definite design consideration.