Memory frequency / performance

  • Hello everyone,

    I've been wondering if memory frequency makes a big difference in performance. For example, my dedicated pfSense box runs on:

    • Xeon L5420 quad 2.5GHz [running stock, adapter to 775]
    • Intel P45 Chipset [Asus P5Q-E]
    • 2 x 2GB DDR2 800 CL5 dual channel
    • 6 x 1Gbps NICs

    I have 2 WAN links, one is 1Gbps down / 200Mbps up through a separate gateway, one is 1Gbps down / 100 Mbps up with PPPoE [which is limited by my config to about 880Mbps down because of the lousy PPPoE].

    I have some spare memory, 4x2GB DDR2 667 CL5 and I was going to install it, but I can't really take the machine offline for too long for thorough testing.

    Can anyone tell me if there will be any significant performance loss from going down to DDR2-667? I tried searching, but I couldn't find anything relevant [maybe I don't know how to search properly].

    Thank you!

  • In short - you probably won't see a big difference in performance.

    Long version - Memory performance really only matters if you use lots of ram a lot of the time. With what you're doing it doesn't seem like that is the case, and anyhow - 667 "Mhz" ram has a bandwidth of 5.3 GB/s and you're running two channels for a combined 10.6GB/s, you'll be perfectly fine.

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