Why is a 1:1 FSB/RAM ratio better?

M

michaelmcgo

New Member
I am trying to OC my E2180 to 3.2 Ghz (400x8) so that my FSB is in a 1:1 ratio with my DDR2 800 RAM. I've heard this is a good thing, why?
 
Having your ratio at 1:1 is a good thing because it saves your RAM speed going through the roof when you're OC'ing your CPU...

It basically halves your RAM speed, so that as you OC your CPU, you start to bring the RAM back up to it's default speed...
 
It is a good thing, but Danny he's asking why a 1:1 ratio gives you better performance.

Sorry, I don't have an answer to your question,
 
[-0MEGA-];927403 said:
It is a good thing, but Danny he's asking why a 1:1 ratio gives you better performance.

Sorry, I don't have an answer to your question,
Click to expand...

I thought he was just asking why it's good, he doesn't mention performance...

:)
 
I've been told it's like this:

If you have a one lane road from the CPU to the RAM and a one lane road from the RAM to the CPU (1:1) theres less chance of a backlog in traffic (data).
Whereas if you have a 2 lane road from the CPU to the RAM and a one lane road from the RAM to the CPU then there's going to be more traffic going into the RAM than the road out (to the CPU) can hold. That will cause a backlog in data and result in lower performance.

That's just an idea.
 
I was wondering about performance.

Currently I am running my CPU at 3.0 Ghz (333x9), with a 1:2.4 Ratio.

I was wondering how much better performance I'd get with my ratio at 1:1 (FSB at 400). Same RAM speed, different ratio.
 
I don't know what the exact difference would be. But as to why 1:1 is better, nffc10 is right, all the clocks line up instead of having to wait at one end or the other.
 
nffc10 said:
I've been told it's like this:

If you have a one lane road from the CPU to the RAM and a one lane road from the RAM to the CPU (1:1) theres less chance of a backlog in traffic (data).
Whereas if you have a 2 lane road from the CPU to the RAM and a one lane road from the RAM to the CPU then there's going to be more traffic going into the RAM than the road out (to the CPU) can hold. That will cause a backlog in data and result in lower performance.

That's just an idea.
Click to expand...

Thanks for clearing that up. :)
 
Is there a performance comparison anybody knows about between 1:1 and not 1:1?

Has anyone tried both setups and noticed a difference?
 
michaelmcgo said:
Is there a performance comparison anybody knows about between 1:1 and not 1:1?

Has anyone tried both setups and noticed a difference?
Click to expand...
I've ran memory bandwidth benchmarks doing that and the 1:1 ratio always was better except for when the memory speed what significantly faster in a non 1:1 ratio.
 
Assuming I keep my FSB at 333, would I be better off with my RAM at 800mhz (1:2.4) or downclocking my RAM to 667 (1:1) and tightening my latencies?
 
michaelmcgo said:
Assuming I can only reach a 333Mhz FSB, would I be better off downclocking my RAM to 667Mhz and running it at 1:1? I could increase my latencies to 4,4,4,12
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You don't want higher latencies, you want them as low as possible. You should be able to easily reach 3-3-3-12.
 
But would it be better performance-wise to have as an exapple: 800MHz with 5-5-5-15 or 667MHz with 4-4-4-12?
 
I can run my RAM at two settings with my CPU at 3.0 GHZ (333x9)

1. 800 Mhz (5:6 ratio) with 5,5,5,15 latencies.

2. 667 Mhz (1:1 ratio) with 4,4,4,10 latencies.

Both run Orthos blend for 8 hours stable. Which should be better?
 
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Sorry to threadjack this...but when you say that 1:1 ratio will have your memory running at half the speed of FSB...is that because 1:1 ratio makes both run at the same clockspeed, and FSB is quad-pumped whereas memory (DDR that is) is only doubledatarate?

-OCer noob

On Topic, if i've understood correctly, running ram at 1:1 667Mhz should be better. Correct me if I'm wrong, but 800 doesn't seem to be *significantly* faster than 667. Plus, you might be able of squeezing a bit more juice outta your system...I think.
 
hackapelite said:
Sorry to threadjack this...but when you say that 1:1 ratio will have your memory running at half the speed of FSB...is that because 1:1 ratio makes both run at the same clockspeed, and FSB is quad-pumped whereas memory (DDR that is) is only doubledatarate?
Click to expand...

Yes.
 
Now someone mention this, i don't know if there any performance gain.
So if i dont oc my cpu, which means only fsb 266 x 4 and my ram only 667 which means 333.5 x 2 and the ratio of 5:4.
Is that means that my ram runs faster than the cpu???
 
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