Most Important OC Factor?

[bofeity]

What's more important to OC: FSB, HT, CPU mhz, or DRAM freq?

My dilemma is such: my FSB can go as high as 340 stable... but then that means my DDR can only run stable at sub-optimal levels at ~1380 instead of 1600... But I can lower the FSB and get stock DRAM freq and decent CPU mhz... with so many confounding variables, which one will give me the most bang per mhz? Which one should I try to max out while compromising the others (like my DRAM in my case)?

What about C1E and LLC? On/off? Both off? So confusing!

 

[bofeity]

I have an unlocked multipler by the way, a 965 C3.

Does it matter if I get a particular clock speed of say 3.6ghz by way of multipler (with stock FSB) or different multipler (lower) and increased FSB? Does FSB increase performance by itself?

Example:
Which is better:
3.6 ghz by FSB 300 mhz x 12 multipler OR
3.6 ghz by FSB 200 mhz x 18 multipler

Or are they the same?

 

[Ben90]

First off, your processor doesn't have a FSB. The FSB your thinking of is the base HT clockrate, which due how the processor is designed, has basically no impact on performance.

Since you have an unlocked multiplier, why not do some math and compromise nothing? I haven't overclocked an AMD machine in years so maybe things have changed a little bit, but IIRC it should be a two step processes.

Step1: Set RAM whatever speed you want
Step2: Set CPU whatever speed you want

Id love to help you more, but i haven't done an AMD in years, and i dont know what bios your using. Also keep LLC on, and C1E off if your getting a lot of crashes for no reason

 

[MrK6]

In most applications, CPU speed > RAM speed > FSB/HT/QPI speed, with CPU speed being significantly more important than anything else. That said, I can't help, I haven't overclocked an AMD system in years either.

 

[bofeity]

First off, your processor doesn't have a FSB. The FSB your thinking of is the base HT clockrate, which due how the processor is designed, has basically no impact on performance.

Since you have an unlocked multiplier, why not do some math and compromise nothing? I haven't overclocked an AMD machine in years so maybe things have changed a little bit, but IIRC it should be a two step processes.

Step1: Set RAM whatever speed you want
Step2: Set CPU whatever speed you want

Id love to help you more, but i haven't done an AMD in years, and i dont know what bios your using. Also keep LLC on, and C1E off if your getting a lot of crashes for no reason

Okay, so it doesn't matter how I get my CPU clock rate? It's the same whether it's through FSB or with multiplier? As my example showed above... ? The important thing is the CPU clock correct? Because for some reason I heard many years ago that a HIGH FSB with the SAME cpu speed with just multiplier manipulation alone is better... this is not true based on what you guys have told me.

 

[deimos3428]

First, the answer to your question is "none of the above". (Though you can probably get a pretty loud *bang* if you set the voltage to the maximum the motherboard allows...so don't do that!)

What matters in over-clocking is stability, cooling, and noise. You aren't likely to achieve a satisfactory result by maxing out any one of the values.

Start at stock voltage, stock frequency, and stock multiplier and increment slowly, testing thoroughly after each increment and watching your CPU temps to make sure you're not going to damage the processor.

You're right that it doesn't really matter how you achieve the CPU frequency, though the method used has some implications for other components. There are three types of over-clocking available to you with the 965:

1. You increase the multiplier: 200x17=3400, 200x17.5=3500, 200x18= 3600, etc.
2. You increase the clock: 200x17=3400, 205x17=3485, 210x17 = 3570 etc.
3. You increase some of each. 202x17.5 = 3535, etc.

The first option increases only the CPU multiplier, so it's easier to do and it doesn't affect other components.

The second option increases only the reference clock which affects the CPU, CPU-NB, and RAM. It will often result in a higher stable over-clock as it's more fine-grained, but it's possible to end up with sub-optimal RAM/NB frequencies if you push the clock too high.

The third option combines these techniques and the benefits of each. You can bump up the multiplier quite a bit, then edge up the frequency further by bumping the reference clock a wee bit. This won't affect your NB or RAM as significantly as #2.

 

[aigomorla]

Example:
Which is better:
3.6 ghz by FSB 300 mhz x 12 multipler OR
3.6 ghz by FSB 200 mhz x 18 multipler

Or are they the same?

The top.

Reason is your FSB is also accelerated.
That means your ram is working faster, your IO's are also working faster.

That also means more stress on your board, and your ram, which leads to additional heat.

 

[lopri]

Most important OC factor = fun.

 

[Ben90]

The top.

Reason is your FSB is also accelerated.
That means your ram is working faster, your IO's are also working faster.

That also means more stress on your board, and your ram, which leads to additional heat.

Im sure you missed its an AMD, the base HT clock by itself has no performance difference between values. If you were able to pull 300 and still keep the base HT multiplier, now that would lead to some performance difference. But unfortunately your going to have to drop the multiplier depending on how much it can handle.

When HT was new technology, even a 50mhz increase would often yield crashes, which meant in extremely IO bound cases, you would lose performance going from bHT 200->210


(im sure you know all this though prolly just missed that its an AMD)

 

[Billb2]

Okay, so it doesn't matter how I get my CPU clock rate?

Run some benchmarks.
Some things benefit from higher FSB (3DMark) and some dontr (SuperPi).

 

[Ben90]

Run some benchmarks.
Some things benefit from higher FSB (3DMark) and some dontr (SuperPi).

Some processors have a FSB (core2s, ect.) and some dontr (the one he has).

 

[Billb2]

Would you be Bern333?

 

[cmdrdredd]

Some processors have a FSB (core2s, ect.) and some dontr (the one he has).

No real FSB but overclocking your various motherboard links and memory past stock specs will give you more overall performance.

 

[DrMrLordX]

Im sure you missed its an AMD, the base HT clock by itself has no performance difference between values. If you were able to pull 300 and still keep the base HT multiplier, now that would lead to some performance difference. But unfortunately your going to have to drop the multiplier depending on how much it can handle.

When HT was new technology, even a 50mhz increase would often yield crashes, which meant in extremely IO bound cases, you would lose performance going from bHT 200->210


(im sure you know all this though prolly just missed that its an AMD)

Raising the HTT will still increase memory speed and NB speed though, while also raising CPU speed in one fell swoop. So, much of the on-die IO will improve (memory bandwidth, memory latency, l3 cache bandwidth/latency). None of that will happen if he OCs by CPU multi alone.

As far as HT multi and HT speeds are concerned, modern AMD systems are a bit less sensitive to HT speeds now. It varies from board to board. My AM2 board could handle HT speeds as high as 1400 mhz (default was 1000 mhz) without much extra voltage, and it can help with some off-die IO if you can pull it off (especially if you're using an IGP or something like that).

As others have echoed here, his best bet will be to find the top OC for his cores and then attempt to achieve that overclock with the best memory latency and NB speed possible. If he OCs the CPU and leaves his RAM and NB alone, he will not get great CPU scaling in any app that hits the L3 and/or system memory frequently.

 

[overclocking101]

why not set your fsb/HT to 340 and run your ram overclocked?? ddr3 does not need to stay at stock freq and has a pretty high oc rate just a thought