[Mallrat]

How do they affect performance. i know the higher the number, the better it is for the most part.

But the new imacs only have 256 of cache but i'm sure they are faster than the ibook with 256 of cache because of hard drive speed.

Overall is there a list at how fast the apple machines are.

I would give the faster one 100 and work my way down.

LIke this.

dual G5 would get the 100
1.8 G5 get 95
1.6 93

what is the speed difference of the previous imacs that are 800 and still on sale for 1100 vs the new ibook g4?

[SupahCoolX]

Check www.xlr8yourmac.com for various benchmarks & performance comparisons. Most benchmarks work up, however (an older, base system gets 100, and newer systems get 110, 125, etc.). Of current systems, PowerMac G5's are definitely the fastest. iMacs and Powerbooks are next. Then the eMac and iBook.

Bus speed is basically the speed at which the main components (processor, RAM, hard drive, etc) communicate with each other.

Cache is a small bit of high speed memory that is directly linked to the processor. This holds some commonly used bits of data, so the processor can repeatedly access them as quickly as possible.

Beware though: Don't go by just the numbers. Different types of cache (L2, L3, in-line, backside, etc) paired with different processors may yield different results. Holding everything else constant, more cache = more speed, but there are other factors that can certainly come into play.

[psk-ele]

SupahCoolX makes an excellent point. For example, in the new AL PB, Apple did away with the L3 cache. This is because the faster DDR2100 or DDR2700 Ram is fast enough that there is no need to store commonly used data bits in the L3 cache to make up for the slower bus speed and memory (i.e.-133MHz). The new iBook g4s would be much more responsive if we kept the L2 cahce the same and added L3 cache. This would in effect be the same as the older TiBooks, and more comparable to the newer revolution of AL PB......

Just think of the cache as the battery in your iBook and the bus speed as your power adaptor. When the bus speed can't keep up with the demands of the system (i.e-you unplug your power adaptor) your cache takes over, feeding information to the processor until the bus is freed up enough to allow data to flow back to the processor (ie-plugging your power adaptor back in). Probably a bad example, but that is how I keep it all straight in my head.............

[andreas_g4]

A good cache-analogy is:

The data the processor needs is a telephone numer.

The L1 cache equals the numers in your brain
The L2 cache equals the numers in your personal phone book
The L3 cache equals the city wide telephone directory.