slashdot is NOT a place for hardware reviews.  slashdot is a place to link to reviews on other sites...so you basically said places like tom's hardware suck.
the reason people like macs for video/graphics is b/c of their floating point unit and the altivec engine.  the hardware in those terms is incredibly good.  liek if you have 2 floating point arrays you want added say assembly would look like...
addvf v0, v1, v2
sv 0(r0), v0
so that'd say add vector 1 and vector 2, store it in vector register 0 and store vector 0 in memeory at the memory location listed in r0.  i don't remember the vector operations in a lot of the x86 machines, but apple's claim to fame is if you have a list of numbers like 1,2,3,4,5 and another list 5,4,3,2,1 after we're doing w/adding the first vector value we can start on the store.  so after adding 1 and 5 we can store it at r0 while our vector floating point unit is still doing the rest of the operations.  in other words, in a fully pipelined situation w/forwarding of results we can do our entire thing in perfect time...i.e. we have a cpi of 1...no pipeline stalls.
on normal x86 machines (like if the compiler doesn't pick up on this optimization or there is no vector unit, which a lot of the x86 machines don't have), this'll be a stall up the ass...most likely # of cycles it takes to do 1 floating point add times the number of items in the vector...that's constly.  otherwise it'll break the entire thing down into a loop of like 10 instructions and you'll have a decent hit b/c of branch misprediction which would range depending on your branch prediction scheme.
that's one of the reasons people use macs...but that's not just for graphics/video stuff.  did that make sense???
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