EXS 24 Logic Sampler Users Group

--- Murray McDowall <murraymc@...> wrote: 
> I can't find any new info on MacRumours or ThinkSecret about whether they
> have done anything about the lack of memory bandwidth 
There isnt a lack of bandwidth as such - as the cpu is one side of the
controller the GFX, Disk and PCI subsytems can all access the memory at full
bandwidth, so it isnt *that* much of an issue for most peoples purposes. This
is still the case in the new machines though.

> (although noise issues have been seen to). 
They have? This is something there is no mention of in the specs. I would
assume it is no quieter until I hear otherwise from someone thats actually
received one.

> If this is so it would appear that the revised G4 with the bandwidth to
> allow the PC 2700 DDR to earn its keep is still not available. It looks 
> like the L3 cache is all that is happening to speed memory access -- not 
> really an adequate solution for DAWs where you are running lots of 
> plugs simultaneously. 
Mmm. I'd disagree. As I mentioned, most memory bandwidth is used either
GFX>mem or disk>mem.  IIRC the CPU->Mem bandwidth in the MDD machines is
approximately 150MB/s. To put that in context, a 24bit 96K stereo audio
stream uses approx 0.56MB/s of bandwidth. Being pessimistic and assuming that
50% of the cpu->mem bandwidth is used up by GFX and IO device access, I dont
think the lack of *extra* bandwidth is a serious constraint for most DAW
users.

If you personally find this to be an issue, I'd be interested to know what
your average track setup is (track count, resolution, plugin use, live input
use and hardware config) I think you're most likely to find you're
constrained by lack of spare CPU cycles not bandwidth to memory! If you want
to work out your bus usage, try having a play with GaugePro from :
  http://www.macgeneral.de/DownloadsHTML/GaugePro.html

Best Wishes,

Dave Peverley

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