Interesting read and links
Might explain slower times on Super PI at HIGHER FSB
http://www.madshrimps.be/?action=getarticle&number=6&artpage=2137&articID=514
A word on Asus P5B-deluxe performance
The motherboard that we are using for our memory roundup is the Asus P5B deluxe/wifi-AP, a motherboard equipped with the Intel 965 chipset. We chose specifically this motherboard because it is capable of attaining very high front side bus speeds compared to motherboards equipped with the Intel 975 or (older) nVidia chipsets. Among the 965 motherboards, the Asus is also one of the better performing boards, often reaching FSB speeds of more than 500FSB. Of course, when we want to test memory overclocking, we need a motherboard that is capable of this high FSB, and one that is compatible with high frequency ram (the 975 chipset is known to give problems with ram over 1000Mhz, sometimes).
Over the last couple of months, many of the highly respected memory guru's like Tony Bigtoe, Freecableguy (FCG), bachus_anonym and EVA2000 (sorry for all those I forget) have been looking for answers where this high FSB performance, and consequently the high memory performance, was coming from on the P965 chipset. At a certain moment, maximum memory speeds were all of a sudden booming all over the internet, and the general feeling was that some "impossible" memory scores were floating around. That's why some answers had to be found.
You must realize that, when you start pumping up the FSB of your motherboard, you are actually overclocking your chipset. Just like memory, chipsets have standard timings and standard voltages, and when you're overclocking you can give a little more voltage to the chipset, in order to make it scale higher. Normally, once you hit 380-430FSB on the Intel 965 and the 975 chipset, you hit an overclocking wall (unless you do some more exotic, warranty voiding trickery of course...) . How does Asus reach 500FSB than ? One of the things Tony found out was that the P5B automatically relaxes (slows down) the timings of the chipset itself in order to be able to scale above 400FSB. There seem to be certain "sets" of timings which are implemented at different FSB settings, and these sets are called "straps". The Asus P5B now sets a different strap when you boot at 400+FSB, than when you boot at 400-FSB, the 400+ strap being the slower of the two. This obviously has a direct influence on your memory bandwidth and on the entire performance of your PC. This will show up in this review as well, when we're looking into the performance of the Team Group's ram, which scaled beyond 400FSB on our settings, and in the process gives worse results than you would actually expect... To conclude : some answers were found already, but others remain unanswered for the time being. Tony and the others are still working very hard to unravel more mysteries, and try to get the motherboard manufacturers on board in the process.
Take a look at this and this thread by Tony Bigtoe over at the OCZ support forums of BleedinEdge, and also at this thread at the XtremeSystems forums. The threads by Tony are in my personal opinion obligated reading for anyone considering to buy a top performing memory kit, just to understand the performance of your PC setup.
Might explain slower times on Super PI at HIGHER FSB
http://www.madshrimps.be/?action=getarticle&number=6&artpage=2137&articID=514
A word on Asus P5B-deluxe performance
The motherboard that we are using for our memory roundup is the Asus P5B deluxe/wifi-AP, a motherboard equipped with the Intel 965 chipset. We chose specifically this motherboard because it is capable of attaining very high front side bus speeds compared to motherboards equipped with the Intel 975 or (older) nVidia chipsets. Among the 965 motherboards, the Asus is also one of the better performing boards, often reaching FSB speeds of more than 500FSB. Of course, when we want to test memory overclocking, we need a motherboard that is capable of this high FSB, and one that is compatible with high frequency ram (the 975 chipset is known to give problems with ram over 1000Mhz, sometimes).
Over the last couple of months, many of the highly respected memory guru's like Tony Bigtoe, Freecableguy (FCG), bachus_anonym and EVA2000 (sorry for all those I forget) have been looking for answers where this high FSB performance, and consequently the high memory performance, was coming from on the P965 chipset. At a certain moment, maximum memory speeds were all of a sudden booming all over the internet, and the general feeling was that some "impossible" memory scores were floating around. That's why some answers had to be found.
You must realize that, when you start pumping up the FSB of your motherboard, you are actually overclocking your chipset. Just like memory, chipsets have standard timings and standard voltages, and when you're overclocking you can give a little more voltage to the chipset, in order to make it scale higher. Normally, once you hit 380-430FSB on the Intel 965 and the 975 chipset, you hit an overclocking wall (unless you do some more exotic, warranty voiding trickery of course...) . How does Asus reach 500FSB than ? One of the things Tony found out was that the P5B automatically relaxes (slows down) the timings of the chipset itself in order to be able to scale above 400FSB. There seem to be certain "sets" of timings which are implemented at different FSB settings, and these sets are called "straps". The Asus P5B now sets a different strap when you boot at 400+FSB, than when you boot at 400-FSB, the 400+ strap being the slower of the two. This obviously has a direct influence on your memory bandwidth and on the entire performance of your PC. This will show up in this review as well, when we're looking into the performance of the Team Group's ram, which scaled beyond 400FSB on our settings, and in the process gives worse results than you would actually expect... To conclude : some answers were found already, but others remain unanswered for the time being. Tony and the others are still working very hard to unravel more mysteries, and try to get the motherboard manufacturers on board in the process.
Take a look at this and this thread by Tony Bigtoe over at the OCZ support forums of BleedinEdge, and also at this thread at the XtremeSystems forums. The threads by Tony are in my personal opinion obligated reading for anyone considering to buy a top performing memory kit, just to understand the performance of your PC setup.
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