Bus Speed vs. CPU speed

[Etruscan]

Greetings:

I need a little help making a clocking decision. I don't have SiSoft installed, so, that's why I need the advice.

I am working on a K6II-450. It is presently clocked at 120 x 4 = 480mhz at 2.2 volts. http://www.sysopt.com/forum/smile.gif I can get the bus speed raised to 130. At 130 I can clock it at 3.5x for 455mhz.

The question is: is it better to have the higher bus speed of 130, an 8% increase or a higher CPU speed at 480mhz a 7% increase?

I can get better multipliers at both speeds, but I have to raise the the core voltage to 2.4 or 2.5 to keep it stable. The high core voltage is what I am trying to avoid right now for everyday use. I'll just save the high voltage for special occasions, I guess, to give the CPU a little longer life.



[This message has been edited by Etruscan (edited 04-21-2001).]

[scotter]

this is what I've found with the K6-2 for chip speeds below 500MHz running the FSB above 100Mhz gains you nothing

for chip speeds over 500Mhz incressing the FSB over 100Mhz gains you performance.

so in your case overclocking with the FSB is only taxing your other system components with no real gain in performance for the extra ware and tare
if you have really good cooling you should see 500to 550Mhz with the K6-2-450
depending on what settings you have for your fsb try 5 x 100 at 2.4 to 2.5 volts for 500 MHZ
or 5.0 x 105 or 5.0 x 10
it might even do 5.0 x 112 for 560MHZ
probably gona need 2.7 volts for that though and your really gona need GOOD cooling
just play around with what your system will do till you get a speed and voltage that your happy with and remember
the main thing is over 500Mhz up the FSB under 500 up the mulitiplier or a combonation of the 2 when your overclocked speed is going to be over 500Mhz.

also as long as you keep the chip under 2.6 volts and it stays cool your not gona do much of any damage to it that your gona see in your time using that chip
I defalt run all K6-2 chips at 2.3 to 2.4 volts from the get go makes them a little more stable http://www.sysopt.com/forum/smile.gif and have not had one die yet in over 3 years of building systems with them http://www.sysopt.com/forum/smile.gif



[This message has been edited by scotter (edited 04-21-2001).]

[Etruscan]

Thanks, scotter, for the, okay, ultimate member advice. You have had a lot of experience running these chips and know what they do. This is my first K6II.

What you're saying is kind of opposite to what I was trying to do; I guess I'll have to change my thinking. http://www.sysopt.com/forum/frown.gif I thought that by raising the bus speed to 120 and 130 Mhz I would get a lot more performance out of the RAM cache, Dimms, and the Bus to the Chip Set - like 20% and 30% respectivly.

However, your experience would seem to fly in the face of my hopes: running a cool chip and still getting improved performance by using the motherboard.

I don't know how the buffers work to these various devices from the CPU. But, by what scotter is saying, the buffers work best at 100mhz unless the CPU is going over 500mhz. The reason I, I suppose, is the CPU can't handle the increased amount of data on the buffers?

I won't have SiSoft on my system for a while so I can't really test. I am sort of in the process of changing over to WinME, a long story too boring to relate now. I guess it's '**** the torpedoes', raise the voltage, increase the CPU speed, pray for rain or a Peltier cooler, and let 'er rip, unless someone else has another idea or contrary experience?

[scotter]

you are correct in you thing the problem with upping the FSB above 100 if the chip speed is less than 500MHz is the chip just cant hanble the extra Through put from the memory system so you dont see any reall increase from the FSB

check this out look at the bottom of the page there are bench mark resolts from my old system http://www.comppwizz.com/overclocking.htm

no look at the 495 and 500 MHz comparision
you will see what I mean

[Etruscan]

Yeah, very interesting results, scotter. I see what you mean about the 495 and the 550 at 110 FSB. The Asus board has a great rep., so it probably doesn't have anything to with the board. Your result at 550 looks pretty good next to a stock PIII 500. I guess I'll fiddle with it a little more, and test as I go once I get SiSoft installed .