Originally posted by Greg
Way out of my league on this, but does it make any sense to have a screaming processor mounted on a board without a buss(sp?) speed that can match it? What about the other chips?
Greg,
Mobo manufacturers use chipsets from the major mfgrs (Intel, VIA, nVidia, & ATI's starting to get into the act too). VIA, et al match their chipsets bus speeds to the external bus speeds of AMD & Intel CPUs. It doesn't do any good to have a higher bus than a CPU will use, it only makes production more complicated & expensive.
A processor's clock speed is a function of FSB (front side bus) times the multiplier. But that alone isn't the measure of a processor's performance, The Mac G4 & G5 chips have a fairly low clock speed, but the handle a large number of instructions per cycle. AMD chips run at a higher speed than the Mac, but perform fewer instructions per cycle. Intel has the fastest internal clock speed, but they perform the fewest operations per cycle. The biggest problem with
speed is the watse heat generated in progressively smaller CPU cores.
Intel has been a "speed" whore for the last couple of years but the P-4 platform has reached the end of it's thermal efficiency/speed lifecycle. (The newest P-4s are mini ovens.) AMD came out with it's "PR" ratings a few years back for comparison purposes with Intel. An AMD XP2500+ chip doesn't actually run at 2.5Ghz, it runs at ~1.8GHz, but it performs about the same as a 2.5GHz P-4.
I use an XP-M 2400+ processor in my main rig. The AMD mobile processors are 'unlocked' for both the FSB & multiplier, so I cranked it up to XP3200+ speeds (200FSBx11mult=2.2GHz). I can run at that speed while still using low, low XP-M voltages - with resultant lower heat. I was also able to buy the CPU for $77 vs $269 for the XP-3200+.
I could crank it up even further, but the voltage will have to go up & heat will go up. (These CPUs will hit 2.4-2.5 GHz on air, 2.6-2.7 GHz with water cooling, and 3GHz or higher if you run a phase-change/peltier cooler!)
Angel