On Feb 1, 2012, at 9:31 AM, MJH Raichyk wrote: > CPU Type: PowerPC G4 (2.9) > Number Of CPUs: 2 > CPU Speed: 450 MHz > L2 Cache (per CPU): 1 MB > Memory: 896 MB > > This is what my profiler says and I'm running Tiger 10.4.11 so how do I plan > my moves, like the iMac as well, this has always seemed confusing with that > 'dual core' idea. Does that dual stuff double my speed maybe, and/or mean my > ram is really double. I was just happy with my system as is, then this > 'word' went around that now even my 10 was going to be history. Took a while > to transition to the 10 from the 9 etc. I do mostly research for simulations > (math or logic models) and writing reports, and now so many articles are > pointing to youtube (which before was not appealing), but now those now > sometimes are universally user friendly... cancel anything with much Flash. > Hope this is adequate to figure out the dual, upgrade scheme for this machine.
Ok, there's a few confusing terms going around. The "Core 2 Duo" and "Core Duo" systems being talked about here are Intel CPU's with two processing cores on the same silicon die, it's one cpu inthat it is one chip; but it acts like dual CPU systems because there are two (or more in later iterations of this cpu design). Your mac has two separate G4 CPU chips on the processor card. Neither will 'double your speed'. What DOES happen is that computing tasks that can be split among two processors will be done in (0.5 + overhead)*the time it would take a single processor of the same speed. That 'overhead coefficient is wildly variable and depends on the OS and CPU's involved. The Core Duo and Core 2 Duo (and later iterations like the i5 and i7) multi-core cpu designs have a much tighter hardware coupling to this behavior, and so your speed is closer to 1/n * core # speed, or even better. This, for example, is the equivalent info from my system (which just over a year old, it was made in October 2010 enter your serial number here <http://www.chipmunk.nl/cgi-fast/applemodel.cgi> to find out when yours was made): Model Name: iMac Model Identifier: iMac11,3 Processor Name: Intel Core i7 Processor Speed: 2.93 GHz Number Of Processors: 1 Total Number Of Cores: 4 L2 Cache (per core): 256 KB L3 Cache: 8 MB Memory: 8 GB I've got the Core i7 4-core system. Due to the design of the iN series of processors, each core can run two processes (called threads) in parallel, so my system is behaving as if it has 8 CPU's. Aside from splitting computationally intensive tasks for true parallel processing, multiple cpu or multi-core systems also offer the ability to simply do more things at once: Word could be running on one CPU and Firefox on the other, which will speed up overall performance. What this means in practice is: If your process is heavily CPU bound (things like rendering video, rendering 3D images, encoding music, anything involving lots and lots of sequential calculations) you will approach (but never reach) a true 2x speedup. If your OS is properly written (and starting with 10.4 OS X was) many things in the OS will take advantage of the multi-core abilities to do more than one thing at a time, giving you a performance boot in everyday use. The CPU manufacturers have tacitly ended the 'gigahertz' wars because they're not getting the leaps in cpu speed that they used to do; increases of CPU speed in modern electronics means that they're runne=ing headlong into quantum and other effects that only happen in very small distances and at very high frequencies. So they've gone the same route used for increasing processing power since the early 80's: packing more than one CPU into the box...in this case packing more into the CPU package. Hence the multicore series of processors noe current in all the major CPU platforms. Even the iPhone now has a dual-core cpu. The improvement gained by using multiple CPUs has been overshadowed in recent years by the increasing use of the extremely powerful and fast processors in video cards to offload some of the CPU load onto the GPU (Graphics processing unit). These chips have a much more limited number of things they do (they make bad general CPU's for this reason) but some things they do very very well; things that can be heavily parallelized work amazingly well on modern GPU's which may have the equivalent of 32, 64 or even 128 'processors') When an os can offload computationally-intensive tasks onto the GPU the performance gains can be on the order of a couple magnitudes different. OS X, starting with 10.5 (and the Core series of API's, Core Video, Core Graphics, etc) makes use of this tactic, so it's really not a 2 CPU == 2x 1CPU calculation anymore. Dragging it back to YOUR case, the best upgrade you could get would be to an Intel-based Mac, provided you're not limited to PPC-only code. A modern iMac or Mac Mini, even the lowest-end one is several times faster than your current system and can run those Youtube videos without a hiccup, AND run the most modern Mac OS. Upgrading your existing system is really not economical; even upgrading to a G5 system is questionable, given the costs and lost opportunity represented by the end of PPC compatibility for many programs. -- Bruce Johnson University of Arizona College of Pharmacy Information Technology Group Institutions do not have opinions, merely customs -- You received this message because you are a member of the iMac Group, a group for those using Apple iMacs and eMacs. The list FAQ is at http://lowendmac.com/imac/list.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to imaclist@googlegroups.com To leave this group, send email to imaclist+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/imaclist
