Higher multipliers or lower multipliers? (Core 2 Duo)

[Steven T]

I have been hearing conflicting information on this. I have heard that a lower multi with higher FSB is better in terms of performance and I have heard that a higher multi with lower FSB is better for hitting the sweetspot and latency reasons.

If I run 8x 425 and run orthos I can stay stable overnight. If I run 9x 377 on the same voltage (which is the same overclock) I crash in 5 minutes. Can someone explain why this is?

I am totally confused... I haven't been able to find a straight answer anywhere.

Asus p5n-e (650i)
e6600
2x 1gb patriot extreme (always running 1:1 w/ FSB)

 

[Steven T]

RAAAWWWWWWWWWWWRRRRRRRRRRRR!! Nobody can ever asnwer this. And i dont understand why not!

 

[ArchAngel777]

Some motherboards have issues with certain bus frequencies. Remember, only 266Mhz is officially supported in the first place. Back in the day, trying to run a bus speed greater than an officially sanctioned one would generally yield mediocre results. Often, you could only push a few Mhz past official spec before things would crap out. Of course, things have changed since then. Anyway, 425x8 should be better performance, so I wouldn't care if I were you. Also, it is said that some chips are sensitive to certain bus speeds as well.

The short answer? No one knows for sure.

 

[Steven T]

Ahh I see... Cuz someone kept telling me I'd be better off doing 9x 333 than 8x 425. And I was very confused. (especially when the latter setup is stable and runs fine in orthos anyway).

 

[magreen]

Often there's an FSB hole between 370-400 FSB where it switches the memory controller from the 1066 strap to the 1333 strap. It depends on the chipset used and the implementation by the motherboard manufacturer. That's probably why 377 isn't stable for you.

When it switches to the 1333 strap the memory controller in your northbridge is running the memory with higher latencies, so you'll see a loss in memory bandwidth and possibly in overall performance until the FSB is raised quite a bit past the point of the strap change. Sometimes that can explain why in certain situations a lower FSB can yield higher performance than a higher FSB. For example, on many P965 boards at 400 MHz FSB it switches straps and performance falls to below the level of performance at 365MHz FSB, even when taking into account the higher cpu speed at 400 FSB.