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Why is SPD on Asus P5B showing 5-6-6-18?


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I'm using 2 gigs of Corsair "Twin2X2048-6400C4" ram that's rated 4-4-4-12. With my Asus P5B Deluxe motherboard, I have the BIOS set to SPD for memory timings. Cpuz shows the memory timings as 5-6-6-18.


Why is this?


I'm running this memory at its default 400 speed (cpu @ 8x400) which gives me 1/1.


Should I just leave it where it is or try for the rated timings? Would there be any real world benefit from 5-6-6-18 to 4-4-4-12?

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I tried it at 4-4-4-12 @ 2.1 volts and it wouldn't boot. The Corsair PDF for this ram says it's rated at JEDEC SPD of 5-5-5-18 for non EPP equipped motherboards and EPP SPD at 4-4-4-12 for EPP equipped motherboards.





I'm a little confused by that.


What timings would you recommend I try (since 4-4-4-12 @ 2.1 volts won't boot)?

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I just tried some various timings and can't get anything other than the SPD 5-6-6-18 (@ 1.9 volts) to boot period! Can't even get 5-5-5-18 (2.1 volts) to boot.


I have all other voltages at Auto.


I guess it has to do with my overclock?

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Here it is. I have the dram set to Auto which automatically makes it match the fsb?








I had to kick it down to 9x356 to get my 3.2 gig. I had it set to 8x400 but Windows XP would freeze after a bit. I think I may have to adjust some voltage to get the 8x400 but I don't know which one to adjust. I have voltages set as follows:


Memory Voltage - 1.9 volts

CPU VCore Voltage - 1.25 volts

FSB Termination Voltage - Auto

NB VCore - Auto

SB VCore - Auto

ICH Chipset Voltage - Auto



BTW, I posted those pics with and but it's only showing as links. Dunno how to post them as pics instead of links. The bottom of my posts show img code as off.

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OK, holy moly I finally got 4-4-4-12. The Auto I was using for Dram Frequency got me all screwed up. It would get me the 1/1 but it had a side effect of limiting the ram to run at 5-6-6-18. As soon as I changed it to DDR2800, I still got the 1/1 but now the ram was running at 4-4-4-12. Maybe you can explain that one to my dumb ***.


Got a question. In the Bios it shows 4-4-4-12 with a TRC of something like 44. Cpuz shows the SPD at 22 for the Trc. Should I move it to 22?

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Usually I do not worry about Trc and set it to Auto. The only time I work with Trc is when there is Tras instability and setting the Trc a bit higher can bring stability.


You will not find any difference between 22 and 25. Your board just does not have an incremental stepping that has 22 as an integer. No big deal at all :)


If you are having no issues at all, then set your Trc lower. I go by Trc = Trp + Tras.

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