AFAIK Nehalem will be running off a 133mhz 'bus'. Our current Intel thinking won't be applied any more. Looking at the way AMD deal with memory speeds vs their bus/HT would be a little more appropiate. We'll be concentrating more on the bandwidth that the CPU has at a certain speed rather than an FSB.
DDR3 - Thought I had this worked out
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AFAIK Nehalem will be running off a 133mhz 'bus'. Our current Intel thinking won't be applied any more. Looking at the way AMD deal with memory speeds vs their bus/HT would be a little more appropiate. We'll be concentrating more on the bandwidth that the CPU has at a certain speed rather than an FSB.
The Nehalem/Bloomfields wont have a front side bus at all. They have an integrated memory controller (max speed currently unknown, but apparently will be DDR3, with some rumors that DDR2 might be possible, though I dont believe it).
The whole 1:1 3:2 2:3 5:4 ratios etc will be history, The memory will run at whatever speed the Nehalems memory controller can manage, though it will probably change in speed as you overclock.. who knows for sure though.
I would guess that intel will select the based 1333mhz DDR3, as with the triple channel interface that is a huge amount of bandwidth. But if you want to overclock then higher speed DDR3 is likely to come into play, and actually be usefull, unlike on current FSB limited systems.
No. A Q9450 at stock speeds needs only DDR2-667mhz (PC2-5300) to run at 1:1. With a 790i board and DDR3 you will be running the memory far faster than the FSB.
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The only reason I can thing of with using 1333mhz DDR3 is to compensate for latency.
7-7-7-20 latency on 1333mhz ddr3 would be approximatly the same as 3.5-3.5-3.5-10 on 667 ddr2 as the latency is in clock ticks, and the DDR3 is clocked at twice the speed.
Think is "Core" processors are fairly tolerant of high latency. And in terms or raw bandwidth its the FSB thats the limiting factor, so the high bandwidth of 1333DDR3 goes to waste.
7-7-7-20 latency on 1333mhz ddr3 would be approximatly the same as 3.5-3.5-3.5-10 on 667 ddr2 as the latency is in clock ticks, and the DDR3 is clocked at twice the speed.
Think is "Core" processors are fairly tolerant of high latency. And in terms or raw bandwidth its the FSB thats the limiting factor, so the high bandwidth of 1333DDR3 goes to waste.
One is a 64bit 1333 bus, the other is a 128bit (2x64bit dual channel) 1333bus. Do the math, the CPU FSB is the limiting factor, hence the need for just 667mhz memory to bandwidth match a 1333mhz FSB processor.
I've a feeling that mixing 780i and 45nm quads isn't the wisest decision if you are intending to overclock.
My nVidia experience is severely limited since the end of my AMD days. But I'm sure helmutcheese will be along to call 780i a POS soon enough.
My nVidia experience is severely limited since the end of my AMD days. But I'm sure helmutcheese will be along to call 780i a POS soon enough.
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Don't CPU's have like three times the bandwidth capabilities of the corresponding RAM?
I remember running memtest years ago, and in the top left corner it reported a CPU bandwidth of 15GB/sec and a RAM bandwidth of 5GB/sec, This was on an A64 3500+ system.
I remember running memtest years ago, and in the top left corner it reported a CPU bandwidth of 15GB/sec and a RAM bandwidth of 5GB/sec, This was on an A64 3500+ system.