The question I have is when apple claims their cpu speed to be dual 1.8 does this mean that
they use two 1.8 cpu's which would combine to make 3.6 or how does this work?
s.

stiggowitz

Dual 1.8 GHz would mean that there are two CPUs (each with
one single core) - each running at 1.8 GHz. With some
processors, this setup is inefficient (especially when
compared with Dual Core which would mean one CPU with
two cores inside). But yes, technically, it makes for 3.6 GHz -
but its hardly as good as having a Dual Core.

Joshua Coventry
Mac dude

It does NOT make for 3.6Ghz! It simply means 2, 1.8ghz G5 CPU's. And dual core is usually SLOWER than seperate CPU's, the reason why is because the dual core setup has to share one bus, one socket. Dual CPU setup's have the advantage of added throughput.

And you must have an application that is built to take advantage of dual cpus. IE. Most OS 9 software is not supported and will only use 1 cpu with exceptions like Photoshop and strata 3D, etc. A good portion of OS-X software is multi threaded and will share the load between both cpu's.

Another thing to remember is that a speed of a CPU is NOT measured by how fast it is. For example, the G5 1.8ghz will easily out perform a higher speed Pentium4 say 2.8ghz. The reason is the G5 is more efficient clock per clock than a P4 CPU. However the P3(or the glorified Pentium 3 called core, core2) ties at about the same speed in integer performance as a G5. However the G5 is leaps ahead of the original P3 in FPU performance and vector processing. In the core versions of the P3 the FPU was improved and will most likely surpass the G5's FPU at the same speed. Dont look at MHz, Ghz, look at MIPS and FLOPS for a more even comparison.

enjoy

Core 2 Duo 1.86
2GB DDR 667
ASUS P5L-MX
Nvidia 8500GT 500/1000