A8N-SLI Deluxe and Memory Timing

Ariel

n00b
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Jan 23, 2005
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I have an Athlon FX-55, an A8N-SLI Deluxe, and four 512MB sticks of Kingston DDR400 PC3200 RAM.

If I put in two of the sticks, it shows "DDR400" when I boot... all four sticks, and it shows "DDR333".

I bought the memory that is listed in the manual as being able to run in all four slots as DDR400... anyone have any idea why it isn't working? I have everything set at "Auto" in the BIOS.. is it safe to manually enter the settings... or should I just take two of the sticks out and live with 1GB ?
 
Ariel said:
I have an Athlon FX-55, an A8N-SLI Deluxe, and four 512MB sticks of Kingston DDR400 PC3200 RAM.

If I put in two of the sticks, it shows "DDR400" when I boot... all four sticks, and it shows "DDR333".

I bought the memory that is listed in the manual as being able to run in all four slots as DDR400... anyone have any idea why it isn't working? I have everything set at "Auto" in the BIOS.. is it safe to manually enter the settings... or should I just take two of the sticks out and live with 1GB ?


That's a known issue, I think AMD 64 CPU's in general will "downshift" to DDR 333 with four sticks, someone correct me if I'm wrong on this though. I've seen a PDF of another board's owner's manual where they even show that with all four sticks populated, that the board will only run at DDR 333 normally.

Here, this seems to confirm what I'm assuming, it's from ASUS' website:

http://www.asus.com/support/faq/qanda.aspx?KB_ID=100091558

Does indicate that you can try setting DDR 400 manually and giving that a go.
 
Yup - I did it and it works.

I had tried it with the beta 1003.005 BIOS installed before, and my system freaked out and wouldn't boot.. but with the "final" 1003, it seems to be fine.

Thanks for the link! :)
 
Ariel said:
Yup - I did it and it works.

I had tried it with the beta 1003.005 BIOS installed before, and my system freaked out and wouldn't boot.. but with the "final" 1003, it seems to be fine.

Thanks for the link! :)


Hey, glad it worked. Lets me know if I decide to get a second 1gb of memory that I can force it to DDR 400 with the right BIOS. ;)
 
When four memory modules are in use, the memory controller of the Athlon 64 can only support DDR400 SDRAM with the slower 2T timing. Moreover, if the four installed modules are two-sided, the speed of the memory subsystem will be dropped to DDR333 even with 2T timing.
http://www.xbitlabs.com/articles/cpu/display/athlon64-3800_3.html

It's they way the memory controller was designed. When AMD releases their E0 stepping it will support four modules at DDR400. I don't know if that will be at 2T.
http://www.theinquirer.net/?article=20780http://www.neoseeker.com/news/story/4235/
 
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