Question on multiplier

[k2000k]

I've just gotten interested in overclocking and soI have been reading a lot about overclocking recently. One question I had was bout the multiplier. I know that you can upp the FSB or alter the multiplier.

For example: Overclocking a 1.8 Ghz Opteron processor to 2.4 Ghz
You can either have the FSB at 267 and the multiplier at 9 getting a clock speed of 2403 Mhz

or

Set the FSB at 300 mhz and the multiplier at 8 getting a speed of 2400 Mhz.

But I remember, think, that someone once mentioned that you do not want to lower the multiplier because it just resulted in the processor being more ineffiecent. I dont know if this is true, so I am asking you guys.

P.S Does a Processor run hotter at 300x8 rather than 266x9?

 

[avatar3k]

I've never heard of such thing. I'd rather be running 300x8 than 200x12, but our wishes just don't seem to come true too often. FSB affects a hell of a lot more than your hard drive, and the general rule is to max out FSB first, not max out multiplier. The processor @ 300x8 is going through 8 cycles per go on the fsb, 200x12 12 cycles per, so the cpu itself is running @ the same frequency. Your system overall will probably be a bit hotter, since in a sense, everything is getting overclocked.

Somebody with more technical know-how might want to jump right in.

 

[NeoSpear]

Well either way your making something hotter if not both. I have an AMD 64 3200+ Venice overclocked from 2Ghz to 2.7Ghz (slightly better performance than an FX55 Clawhammer and way under the price)

The way i did that was to keep the multiplier at 10 and overclock the fsb to 270 which made it very very hot. So i just got a new cooler for it. My cpu ran as cold as a tramp on the street however with a Zalman 7700Cu. I also had to reduce the HTT to 4 rather than 5.

I would recomend keeping the stock multipier and overclocking the fsb because at 300Mhz fsb your gonna be needing to bump up its voltage and thats very risky heat wise. Then your also keeping cpu's efficiency.

Just make sure you have some nice cooling and you'll be fine with upping the cpu's voltage. (my 3200 is at maximum voltage it can go load temps r only 40-45C)

Hope i was some help. :?:

 

[avatar3k]

what components are you working with? not everything can hit 300fsb, etc.

 

[k2000k]

Im not talking about any components in paticular. I picked the Opteron solely because I was reading something about it while I was posting. When I do get a new processor I will probably want to stick with the stock cooler, but if I could not get to my overclocking goal without it then I would buy a new cooler.

 

[scoyle]

Your FSB should be as close to your RAM as possible, when your CPU multiplier is unlocked. Synchronous transimission of data is much better than having the CPU wait for data from the ram, or vice versa.

I'm not sure if it's the same with the Athlon 64, as it has an integrated memory controller, as well as HTT bus technology with which it communicates with the Northbridge, but older motherboards would use the FBS to talk to the northbridge, which was designed to handle 200Mhz frequencies. When you would overclock your FSB higher than 200Mhz on these devices, the temperature would rise or fall in direct correlation with the frequency you're running at.

So your RAM is your limiting component when overclocking your fsb on a CPU with an unlocked multplier. I would adjust my FSB to run at the highest frequency the RAM could handle if my multiplier was unlocked.