DDR2 RAM - How Fast is it Going?

Posted on 2009-02-10
Last Modified: 2013-11-10

I've built my first PC.  I am wondering if my RAM is operating at its optimum speed.

Mo/bo Asus M2N-SLI Deluxe with BIOS ver. 1604
AMD Athlon 64 X2 3800+
WD SATA II 200 GB & 500 GB drives
EVGA nVidia GeForce 7600 GS with 256 MB
Windows XPP SP3
Wintec  AMPO 1GB (2 x 512MB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory Model 3AMD2800-1G1K-R

How do I see what the RAM is rated?  Should I expect to see it rated at 800 MHz?

Question by:Robert

    Author Comment

    I'veinstalled PC Wizard from

    The RAM shows up correctly as 1024 MB, and shows the two as 512 MB [Type] DDR2-800 PC2-6400 (399 MHz).

    More detail from PC Wizard -
    Supported Frequencies :      399 MHz, 400 MHz
    CAS Latency (tCL) :      4 clocks @399 MHz, 5 clocks @400 MHz
    RAS to CAS (tRCD) :      5 clocks @399 MHz, 5 clocks @400 MHz
    RAS Precharge (tRP) :      5 clocks @399 MHz, 5 clocks @400 MHz
    Cycle Time (tRAS) :      18 clocks @399 MHz, 18 clocks @400 MHz
    Min TRC :      23 clocks @399 MHz, 23 clocks @400 MHz
    So it seems like it's running at 400 MHz, not 800 MHz.

    LVL 47

    Accepted Solution

    400 MHz is correct.

    See here for the specifications.
    LVL 33

    Assisted Solution

    Correct. DDR stands for Double Date Rate
    400MHz is the base bus speed, time 2 gets you 800MHz

    There is a chart about half way down:
    LVL 33

    Expert Comment

    I'm going to start refreshing before I post.   ; )

    Author Closing Comment

    Great - I thought that might be the case - but guessing is a good way to screw things up!
    LVL 33

    Expert Comment

    Thank you much.   : )

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