It's your multiplier. The (front side) bus runs at a fixed speed. The processor also runs at a fixed speed. The closer they are to the same speed, the less cycles the core has to wait. In theory, the closer the bus speed is to the chip speed, the faster the system works. In practice, there is only so much bandwidth a chip needs. There can also be variences due to harmonics. (so 1/2 is better than 451/900)
A CPU running on a 200 MHZ bus, one has a 10x multiplier, one has an 11x. The 11x multiplier will be faster, simply becuase the overall gain from the increase in performance of the chip. However, it won't be 10% faster.
ahan so what ratio should one look for? wot should be considered bus or core freq. also how does this thing effects performance in AMD processors? is there any comparison between Intel and AMD processors based on this Bus/Core Ratio?
Unless you have an FX or EE series of cpu, your cpu multiplier is locked (can only be adjusted downward)...
leaving really only the basic 200 MHz clock to be manipulated. in which the this basic clock affects the HTT (normally 5x), mem clock speed (normally PC3200/200 MHz (400 MHz DDR)...
If you have mem capable of running 250 MHz for instance (usually timings will have to be relaxed compared to 200 MHz, and DDR voltage boosted. dpending on mem and mainboard), the HTT (AMD cpus/chipsets only)will be adjusted to 4x (leaving same 1000 MHz with 250 x4), and the cpu multiplier may be adjusted downward (if cpu core is not capable of 25% OC), allowing a lesser cpu overclock, but higher performance in mem bandwidth sensitive applcations due to the higher mem clockspeeds....(If mem is value ram, then the cpu may still be overclocked by cranking up the basic clock speed, while adjusting mem clock dwonwards so that the mem starts off at lower freq initially, so that after OC, the mem is at/near 200 MHz...)
Many people spend numerous hours altering /tinkering with cpu multipliers, mem timings/mem clocks while finding optimum fsb/mem ratios for best performance with utter stability...
You would want to head to the overclocking forums for much more detailed descriptions
Ive been trying to figure out the answer to this question for a couple of days. I have a Intel Pentium 4 Processor 2.6Ghz, 512kb cache, 400Mhz with a Bus/Core ratio of 26 and a Intel Pentium 4 Processor 2.4Ghz, 512kb cache, 400Mhz with a Bus/Core ratio of 18. My question is if anyone knows what processor will give me the best performance. Any help would be greatly appreciated, thank you in advance.
the reason why a 1:1 buss works best is because the data can be directly transfered
If the ratio is out of sync, then the system has to buffer the data. It's like you delivering a package. If you arrive with the package at the same time as the guy arrives to pick up the package, you can just hand the package to him. If you arrive early or late, then you will have to put the package in a drop box. Neither you or the other guy will wait around, you get there and if nothing is there, you leave. You can see how it adds "latency".