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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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esveezy

Registered
Joined
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.
 

Shiggity

Member
Joined
Dec 16, 2007
Location
Chicago, IL
I use Everest Ultimate Edition's cache/ram benchmark tool to see the differences timing adjustments make.

http://www.download.com/Everest-Ultimate-Edition/3000-2086_4-10499291.html?tag=lst-1

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.
 
OP
esveezy

esveezy

Registered
Joined
Sep 11, 2007
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.