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How important is the 1:1 FSB:RAM ratio? Better than 1:1.2 (5:6) with the same FSB?

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Sep 11, 2007
How important is the 1:1 FSB:RAM ratio? Better than 1:1.2 (5:6) with the same FSB?

I've never seen bechmarks indicating just what kind of advantage a 1:1 ratio gets you, and yet I hear it mentioned all the time. Obviously, if your RAM can't take the MHz, your lowest divider may help your max FSB, but I don't think my RAM is holding me back, and I think it might be better to bump it up a notch.

Here's the thing. My X3210 will run right up to 400x8 at stock volts, and with just a bit more, it will go to 450x8. Beyond that, too many volts are needed for daily usage on air cooling, so I'm not worried.

My IP35 Pro also handles a 450 MHz FSB at all minimum volts for its parts, so that's good.

With the FSB set to 450, my new G.Skill DDR2-1000 is only running @900 at 1:1, but I'm sure that a touch more tRFC will allow me to use the 1:1.2 (aka 5:6) ratio and run @1080 (hell, it ran 6 hours of large FFT at stock tRFC of 52 @1080).

Would I be better off spending my time tweaking latencies @900 (1:1), or getting it stable @1080 (1:1.2)?

Also, I think my hardware (8x CPU multi, and DDR2-1000 2x2GB RAM) and overclock (450MHz FSB) is pretty common stuff, so I bet a lot of folks have either dealt with this, or would benefit from the information.

If you know any good articles discussing RAM multipliers, or anything that would be of use, I would really appreciate links.
I use Everest Ultimate Edition's cache/ram benchmark tool to see the differences timing adjustments make.


Your best bet is to either run 900MHz 4-4-4-12 or 1080MHz 5-5-5-15. If you really want to overclock your ram, you could try a 4-4-4-12 timing @ 1080mhz.

You should also give this article a good read. It's about the asus rog rampage motherboard, but within the article is really relevant information about memory overclocking.
Shiggity, thanks for the links, that's just what I needed.

One thing though - 2GB sticks won't stand a chance at 900MHz 4-4-4-12 let alone 4-4-4-12 timing @ 1080mhz. 1080MHz 5-5-5-15 seems possible though.