Phenom II X4 920 HT Link & NB Frequency Questions

[Modular]

So I'm trudging through getting this CPU overclocked and have a basic question about the HT Link and the NB Frequency:


As I understand it, it doesn't make much difference how high these settings are as long as they aren't slower than your RAM speed. Is that correct? I currently have Corsair XMS2 DHX 2x2GB sticks running at 800Mhz and my HT Link and SB Frequency at 1680.

Would it make sense to get the HT Link and SB Freq up higher (the next step up would be my FSB*8 which would get me 1920 on those two settings)? I don't want to do it if it's not going to make any difference in overall speeds and I can't find the optimal speeds for them on the web anywhere.

 

[StrangerGuy]

Overclocking the HT link and SB freq is completely useless.

NB freq on the other hand affects the latency of the L3 and going from stock to 2600MHz makes a significant difference.

Since you can only overclock your BCLK your best option is to raise the FSB as high as you can while turning down the multipier of the HT link/SB freq down by 1 or 2 to preserve stability.

 

[(sic)Klown12]

The HT Link speed doesn't mean much in a single socket system since the extra bandwidth isn't needed. The NB frequency control the IMC and L3 cache. Speeding that up will help with performance by lowering memory latency and upping the bandwidth of the L3 cache.

You don't have to run them lower than your memory, but the NB can't be lower than the HT Link. Try getting the NB up to 2400-2600Mhz to get the most from your over-clock.

A minute late...

 

[Modular]

Thanks for the tips. Just to clarify; I meant NB Freq, not SB Freq. I left SB where it started, at 100Mhz.

A few more questions:
- What is the stock HT link frequency? Is having it at 1680 too slow?
- I'm assuming that getting the NB Freq up to 2400-2600Mhz is going to take a voltage boost. Is this recommended with the stock cooling solution? My motherboard is the Biostar TA790GX 128M, it's not actively cooled at this point.
- I generally use this PC for gaming, will having the NB Freq that high help a bunch, or are the returns diminishing?

 

[(sic)Klown12]

Stock HT Link is 2000Mhz. I've ran it as low as 1400 and didn't see any difference in performance.


Put the voltage for the IMC at 1.2-1.23v and you should be able to hit 2.4Ghz without adding too much heat. Just beware that there might be more than one voltage setting having to do with NB, with one being the IMC and the other referring to the chipset. Which one is which depends on the mobo as they tend to label these things differently.

 

[dorion]

- I'm assuming that getting the NB Freq up to 2400-2600Mhz is going to take a voltage boost. Is this recommended with the stock cooling solution? My motherboard is the Biostar TA790GX 128M, it's not actively cooled at this point.

The NB frequency(the one that makes your L3 and memory access faster) will affect the heat output of the processor, your motherboard should be fine.

 

[busydude]

Stock HT Link is 2000Mhz. I've ran it as low as 1400 and didn't see any difference in performance.

For Phenom II 920, the default HT link speed and NB frequency is set at 1800 MHz..

Do not bother fiddling with HT link speeds..it is useless.

- I generally use this PC for gaming, will having the NB Freq that high help a bunch, or are the returns diminishing?

OC'ing NB frequency give you significant gains especially in games .. and yes, you need to bump the voltage and I don't think stock cooling will be able to handle it. Just invest in a decent after market cooler.. it is definitely worth it IMO.