FS high or low?

95thrifles

95thrifles

95thrifles

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Ok I'm reasonably new to OC'ing but think I have a fair understanding, I was just wanting to get a snapshot of peoples opinions. I see quite a few people on here who have OC'd their FSB to almost 600MHz to get a nice CPU clock, often with lowering the multiplier. However having read anandtechs review of my mobo, they seem to imply it is better to keep your FSB down for your RAM, in that you can get much tighter timings with a lower FSB where as as you increase FSB you need to overvolt your RAM and your timings get loose.
What do people think? Is there a generally accepted right way forward? or is it all personal preference?
 
For max overclocks you will need to push the FSB. You can usually change the divider for fsb:ram ratio to compensate for a high FSB but you may need to slacken off the timings and overvolt your memory. Some boards will let you run your memory unlinked from the FSB so that you can keep your FSB high without yor ram holding it back but it gets mixed reviews as to whether it is very stable or not.

Personally i prefer to find a balance for my system as a whole. Its all very well having insane FSB and clock speeds but if your memory is overvolted and running slacker than a $10 Ho then I dont see point.

Its been a while since i played with any of he newer boards though and my system is getting on for 2 years old. I cant wait till feb for a new rig to fiddle with :D
 
As above really, if you get the higher quality RAM or the faster stuff, then you can whack the FSB up quite high (the Ballistix 667MHz stuff could clock to silly speeds though it did compromise the longevity).

It is often useful to play around with multiplier/FSB to find a sweet spot and it will also allow you to find what your limiting factor is with the overclock.

Even after all i have said, you have a pretty decent overclock yourself :D
 
Anandtech are correct.

With the current P35/P45/X38/X48 boards, the optimum memory bandwidth and latency is achieved somewhere in the middle, with MCH latency (tRD / Performance Level) playing a large part, somewhat larger than FSB speed.

Of course, this will change again with i7, since the MCH will be on-die.

No offence to anyone in particular, but OcUK is not a particularly advanced forum and most people will just reply with "max out your FSB and get the most expensive memory" without much thought or evidence behind the reply.

I would recommend XS, TechReport and Anandtech if you want to learn more.

Having said this, if you are stuck with a low multi CPU, then you have no choice. If you are in the optimal position of having a CPU with a decent (10x or higher for example) multiplier and a motherboard that allows tRD timing adjustment, then you have maximum flexibility and can 'dial in' the best settings. These will most likely be the highest CPU speed possible, followed by the highest FSB while keeping tRD as low as possible, followed by the highest memory speed / lowest memory timings.
 
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RAM latency timings offer little boost with Intel systems - 5% max.

Benefit of a high FSB is more overall bandwidth through the Mobo, CPU and memory controller.

The RAM will perform better at higher speeds with slacker timings in most applications.

Golden rules is to test. Massive CPU clock doesn't always equal more speed. I've clocked systems before and found the CPU 'faster' 100-200MHz slower than its fastest achievable overclock. This sometimes happens when its been pushed too far but just not far enough to become unstable. All sorts of things can go wobbly meaning operations are run a number of times - i.e. making mistakes that have to be executed again.

Its always wise to write down your settings and run the same suite of benchmarks then you can see which overclock has most benefit. Its all about balance. :)

Jimbo Mahoney said:
No offence to anyone in particular, but OcUK is not a particularly advanced forum and most people will just reply with "max out your FSB and get the most expensive memory" without much thought or evidence behind the reply.
Click to expand...

:eek:

Hope I've proved you wrong. ;)
 
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