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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Starcraftfreak - Friday, September 30, 2005 - link
So you are saying, the Board supports the dividers for DDR500 also on a Revision C core? I can remember when you published an article explaining it's a new feature of Revision E. Please clarify.SLI - Wednesday, September 28, 2005 - link
Everything I have seen thus far on the ATI chipset points to the FSB dropping to DDR333 *IF* you populate all 4 DIMM slots (with DDR400 RAM) This was an issue at the CPU level with AMD Athalon on board memory controller (at first) but has been addressed with the newer steppings. VIA and Nvidia chipsets have support for DDR400 with all 4 slots populated. This is a very important aspect to me and it needs to be addressed.Wesley Fink - Wednesday, September 28, 2005 - link
It was addressed in tRAS and Memory Stress Tests in the review - p.5. We had no trouble with 4 dimms at DDR400, though we did have to drop to 2T with 4 dimms as we do on every other AMD chipset. This is more a function of the on-CPU memory controller.sxr7171 - Wednesday, September 28, 2005 - link
I don't get it. We switched to SATA to get worse performance? SATA performed worse than IDE in every single benchmark.Scarceas - Tuesday, September 27, 2005 - link
I'd like to know what happens when you try two 6800s in a crossfire motherboard...I'm also curious about what happens why you try crossfire graphics cards on an NF4 SLI motherboard...
Early on I heard rumors that the motherboard implementation would be similar between the two and that mixing motherboard/graphics manufacturers *might* be possible...
Now the hardware is showing up and no one has tried it?
vailr - Tuesday, September 27, 2005 - link
Check: page 11 "Ethernet Performance" has format errors:http://www.anandtech.com/cpuchipsets/showdoc.aspx?...">http://www.anandtech.com/cpuchipsets/showdoc.aspx?...
Copied & pasted:
It will almost always be <em>much</em> lower than what we have measured.<br /> <br /> </span> </div> <div class="adcontainer"></div> <table border="0" width="100%"> <tr> <td align="right" colspan="2"> <table border="0" cellpadding="0" cellspacing="0"> <tr> <td><strong><a href="showdoc.aspx?i=2542&p=12" class="smalllink">Audio
tanekaha - Wednesday, September 28, 2005 - link
Ethernet page has same problem as b4 hereI`m using firefox latest beta and the browser considers the page done after this line.
Ntttcpr - m 4,0,
I guess u use a template for these reviews I had exactly the same prob with ( and commented similarly ) with I think the asrock dual article.
I guess not many others are getting this prob but I`m glad 2 see some! else has a prob and not just me.
What browser are u using ?
Wesley have u tried 2 view the article with firefox beta ? or even firefox ?
Wesley Fink - Thursday, September 29, 2005 - link
Articles are created in a document engine by our Web Editor, from basic information layouts we send the Web Editor. The engine generates HTML code. We don't individually generate the code for articles. Any problems with viewing the pages should be emailed to our webmaster Jason.Clark@anandtech.comtanekaha - Thursday, September 29, 2005 - link
Thanks for the replies gentsI am not using any blockers or extentions .. apart from FF default pop up blocker.
I will mail jason with the facts (as I see them)
I`ll also send the info to the FF team
THX again
tanekaha
JarredWalton - Wednesday, September 28, 2005 - link
If you're using any extensions to block ads or other content, you might want to try disabling those. I've been using Firefox for over a year now, and I don't have any issues with the pages. (Some pages render improperly the first time and I need to hit refresh, but that's generally only on long pages, and it seems more of a FF bug than anything.)