Gang,
Here is the real point in the review of the 12 Core unit from MacWorld:
As shown in our "Fastest Macs money can buy" report, the 12-core Mac Pro was not the overall speed king in our tests. It was outperformed by a $3699 built-to-order (BTO) Mac Pro with a 3.33GHz 6-core Xeon Westmere processor, which was faster in 10 of our 17 tests, and matched the 12-core Mac Pro’s scores in two other tests. Testing the 12-core Mac Pro with 12GB of RAM (six 2GB DIMMs provided by Crucial) showed very little improvement over the 12-core Mac Pro with 6GB of RAM—just one Speedmark point.
Ok so using their test we basically come up with the following numbers:
Six Core 3.3GHZ, 3G memory: 263
12 Core 2.66GHZ, 6G memory: 261
Quad Core 3.2GHz, 3G memory: 223-231 interpolated data from 2.66 & 2.8 numbers.
8 Core 2.4GHz, 6G memory: 216
Quad Core 2.8GHz, 3G memory: 207
All of these run the same 1066MHz memory and therefore the same speed. But as you will see below, none of these are sold with optimal memory amounts.
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Some people have asked since DP is only a 32 bit application, will using more than 8G really matter.
DP as well as logic, garage band heck even iTunes will require allot of what is called Virtual Memory (VM). There is a pool of memory set aside by the kernel for VM use in all applications. This pool is ever expanding and contracting depending on what is required etc... but say an application asks for X-VM and other applications are asking for Y-VM. If the application for Y-VM is running and has access to the pool (real memory), then the application for X-VM is really sitting on a hard drive. When application X goes to access X-VM, then a lot of things happen which really drag down a system. First X-VM app is paused then application (or thread) Y-VM is paused and the kernel writes Y-VM to disk. Then reads out X-VM into the pool and lets application X-VM do it's stuff.
Now if we have a ton of freaken memory then the pool is very large and what happens is the OS does not need to hit the disk. Everything is local... it does not matter than DP is 32, much of it's memory storage is VM and therefore more memory is better.
Intel & Memory... ok.
It is always best with the Intel system to make sure all your sticks are the same size. Using different sized memory is really bad from Intel sake.
You are really best to increment memory as follows:
1G, 2G, 4G, 8G, 16G, 32G... etc.
Using disimilar sizes can lead to slow downs in the access of memory which is always bad considering the memory here is a slow bottle neck.
Activity Monitor is for kids, if you think that this is telling you anything you are totally wrong. Sure it gives you basic stuff... and will show red line... but really if you are in the red you are really way past it as the AM utility is really conservative.
If you want a better perspective open the terminal (applications->utilities->terminal). This will load the UNIX terminal application. Type in "top" this is the system process display utility in UNIX it will show real time processes, threads, application, memory use, VM, process active, CPU usage per process etc... like this:
Processes: 61 total, 4 running, 57 sleeping, 286 threads 08:37:50
Load Avg: 1.79, 1.86, 1.75 CPU usage: 58.13% user, 8.83% sys, 33.2% idle
SharedLibs: 5568K resident, 7664K data, 0B linkedit.
MemRegions: 18083 total, 1766M resident, 23M private, 741M shared.
PhysMem: 976M wired, 3250M active, 1911M inactive, 6136M used, 2057M free.
VM: 132G vsize, 1042M framework vsize, 11497162(8) pageins, 747(0) pageouts.
Networks: packets: 2893530/3376M in, 2515235/916M out.
Disks: 3538988/84G read, 3671678/681G written.
PID COMMAND %CPU TIME #TH #WQ #PORT #MREG RPRVT RSHRD RSIZE
16376 top 6.4 00:04.23 1/1 0 24 33 1204K 264K 1780K
16372 tcsh 0.0 00:00.02 1 0 17 25 604K 244K 1152K
16371 login 0.0 00:02.84 1 0 22 53 480K 244K 1584K
16369 Terminal 2.2 00:00.56 6 2 109+ 114+ 3232K+ 28M 9880K+
16186 mdworker 0.0 00:42.46 3 1 51 88 9452K 10M 63M
15500- firefox-bin 12.5 34:22.58 11 1 225 1760 89M 101M 306M
14858- DesignWorks 0.1 02:22.97 3 1 127 319 9492K 64M 19M
14849 Grab 0.0 00:07.60 2 1 159 173 8336K 38M 16M
13349- thunderbird- 0.0 16:42.64 13 2 216 821 68M 106M 167M
13302 hdiejectd 0.0 00:03.84 2 1 34 43 596K 524K 1624K
13297 diskimages-h 0.0 00:03.03 3 1 75 69 9548K 10M 13M
2443 AppleSpell 0.0 00:01.66 2 1 35 62 3520K 9344K 9416K
1913* LaunchCFMApp 0.6 36:36.26 4 0 135 350 25M 31M 38M
1890* LaunchCFMApp 0.9 46:53.51 8 0 193 443 42M 47M 59M
I have basically running right now Thunderbird, Firefox, Adobe Reader, HP style calc, Drop Zip, Grab and Design Works (electrical schematics and stuff).
You can see that my VM is actually 132G in size.
I have seen activity monitor show like 5% usage with iTunes/Pure Music or Amarra. Then I run top in the terminal and see the CPU usage jump to almost 55% when outputting 24/192 stereo material. Granted this is only a mac mini 2.4G/8G/200G SSD but still you get the idea.
Thanks
Gordon