nV News Forums


nV News Forums (http://www.nvnews.net/vbulletin/index.php)
-   Benchmarking And Overclocking (http://www.nvnews.net/vbulletin/forumdisplay.php?f=24)
-   -   AMD Phenom II X4 965 Increasing Multiplier vs FSB (http://www.nvnews.net/vbulletin/showthread.php?t=154330)

UberRN69 08-21-10 07:52 PM

AMD Phenom II X4 965 Increasing Multiplier vs FSB
OK, I'm sure this is post prior but a search gives too many results.

Just picked up a 965BE and a MSI 890FXA-GD70 motherboard (Just a lower cost upgrade this time). I'm coming from a Q6600 (I'll post it FS soon) which I OC'd simply by adjusting the FSB from 266mHz to 345mHz to get a OC of 3.11GHz.

I'm noticing that with the Phenom's, people are only increasing the multiplier and pretty much leaving the FSB alone (I only spent about 45 minutes searching this, so maybe I'm wrong).

Is there a reason for this. I always thought that increasing FSB would not only increase your OC, but improve MB bandwidth.

Any incite would be appreciated.


ragejg 08-21-10 09:27 PM

Re: AMD Phenom II X4 965 Increasing Multiplier vs FSB
Almost all people with Black Edition Phenoms up the multiplier. :) I've done that with my two x3 720BE's with good results. With a regular Phenom you're stuck using the FSB which makes things a little trickier. Like you said though, it does increase bandwidth, but the thing there is that you have to make sure all of your other components can handle that extra bandwidth, like your RAM. I'm receiving my x6 1055t soon which is not a Black Edition, so I'm going to soon experience the trials of FSB (HTT) overclocking again. :) I remember the days before PCI locks and dividers when this stuff was much more finnicky... but I found a kinda special Abit KT266a board that could handle up to 193 fsb, a GF3 ti500 that could handle 83mhz AGP, and an SBLive! 5.1 that could handle high PCI speeds... and I coupled that stuff with some high-speed RAM and a 200 fsb capable Athlon XP chip and ended up with a very high-performance rig.

UberRN69 08-21-10 09:50 PM

Re: AMD Phenom II X4 965 Increasing Multiplier vs FSB
Thanks for the reply.

While increasing the multiplier is the easiest, most direct way to OC your CPU, I would have just thought that bumping the FSB to let's say 233mHz would just be another component to OC'ing.

But almost all of the searches I dug up guys were pretty much not touching the FSB, maybe an increase to 208mHz. It left me wondering if AMD CPUs freak out with FSB increases.

Viral 08-22-10 03:05 AM

Re: AMD Phenom II X4 965 Increasing Multiplier vs FSB
They're fine with base clock ("FSB") adjustments as long as you set the Hyper transport multiplier lower accordingly. If you don't do that you will get instability at around 220MHz+ because the HTT bus is running out of spec. The gains over using just the multiplier won't be noticable though so most people just use it for small adjustments to get that last bit out of their chip.

You'll see the more gains from finding your max stable overclock for the CPU and then also try overclocking the north bridge clock which controls memory and other functions. Standard it's only set to 2GHz so if you can get it to 2.5-2.8GHz it makes a noticable difference.

Madpistol 08-22-10 08:37 AM

Re: AMD Phenom II X4 965 Increasing Multiplier vs FSB
Setting the North Bridge higher will yield performance gains. If you just up your CPU multiplier to 19x (3.8Ghz) and leave the NB alone, you will see a performance gain. However, if you up the NB frequency, you will see more data throughput, and thus, performance will actually be better than if you just increase the multiplier. Remember, though, that if you increase the NB frequency, you will have to increase the NB voltage as well. Since the NB is on chip on AMD processors, it will increase heat output on your processor, so be mindful of that.

It's a balancing act between heat and performance, though the sweet spot for the NB is around 2400-2600mhz. Above that is nice if your board/chip can handle it, but remember that heat will increase dramatically if you set the NB voltage over about 1.2v.

That's been my experience. Check out AMD's forums if you're dead set on becoming an overclocking pro on these chips. Those guys have a lot of insight. :)

For reference, I've got my 965BE at 3.8Ghz. I left the multiplier at stock (17x) and increase the FSB to 224mhz. I've got my FSB multiplier @ 11x, so NB is 2464mhz. Memory is at about 1500mhz.

Voltage at this level will vary based on your chip's capabilities.

Johnny C 08-22-10 09:27 AM

Re: AMD Phenom II X4 965 Increasing Multiplier vs FSB
See sig for my Phenom O/C....

UberRN69 08-22-10 10:10 PM

Re: AMD Phenom II X4 965 Increasing Multiplier vs FSB
:wonder:Thanks for all the feedback, cleared it up nicely.

All times are GMT -5. The time now is 03:47 AM.

Powered by vBulletin® Version 3.7.1
Copyright ©2000 - 2015, Jelsoft Enterprises Ltd.
Copyright 1998 - 2014, nV News.