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how much memory is enough ?

My photoshop files are not that big ( < 100mb usually). most of the time i use Lightroom.

Im thinking maybe 8gb is enough to start (2x4gb) and then I can get another 8gb later on to fill up the 4 slots. Im hoping there will not be any noticeable difference running in dual channel rather that triple.
 
12GB or 24GB is the sweet spot with a single-processor Mac Pro. You will notice a speed improvement running 3 sticks of memory in stead of four (I sure did), I was running 16GB and I took out one of my sticks and now my whole machine is notieceably faster and no lag when using the internet, booting apps, or pulling down menus, everything is instantaneous. 12GB is enough for me, but 24GB is great too. Just make sure you leave the slot closest to the processor empty, that way you will be taking advantage of triple-channel memory acceleration running 3 sticks in 3 slots.
 
WardC said:
12GB or 24GB is the sweet spot with a single-processor Mac Pro. You will notice a speed improvement running 3 sticks of memory in stead of four (I sure did), I was running 16GB and I took out one of my sticks and now my whole machine is notieceably faster and no lag when using the internet, booting apps, or pulling down menus, everything is instantaneous. 12GB is enough for me, but 24GB is great too. Just make sure you leave the slot closest to the processor empty, that way you will be taking advantage of triple-channel memory acceleration running 3 sticks in 3 slots.
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Everything you listed there would never, ever saturate dual channel, let alone benefit with triple channel! Im sorry but that improvement you quoted is placebo...

If you were hammering all cores using Photoshop or did computation that hammers the memory bus interconnect then you'd notice improvements. You wouldn't 'pulling down menus'.

Sorry :p

The difference is something like 7Gb/Sec vs 9Gb/Sec, because Safari SO needs that extra 2Gb/Sec :p
 
Dude, you don't know anything about what you are talking about. My RAM display in Activity Monitor is totally different when I have 12GB installed vs 16GB. It shows most of free memory as BLUE as opposed to GREEN when I am running 3 sticks instead of 4. And yes, it's faster, alot faster, my whole system is faster. I even ran the memory tests on Geekbench and XBench, and not only did my memory speeds improve, so did my Processor Integer and Floating Point scores. It's faster with three memory slots full instead of four.

You don't know what you are talking about.
 
WardC said:
Dude, you don't know anything about what you are talking about. My RAM display in Activity Monitor is totally different when I have 12GB installed vs 16GB. It shows most of free memory as BLUE as opposed to GREEN when I am running 3 sticks instead of 4. And yes, it's faster, alot faster, my whole system is faster. I even ran the memory tests on Geekbench and XBench, and not only did my memory speeds improve, so did my Processor Integer and Floating Point scores. It's faster with three memory slots full instead of four.

You don't know what you are talking about.
Click to expand...

LOL Mate, don't start. I've been overclocking and tweaking computers for 10 years.

I know exactly what I'm on about. The fact you quote synthetic benchmarks proves YOU know nothing.

The CPU scores increase because the tests they conduct saturate the memory bandwidth, video and ESPECIALLY photo editing under 99% of conditions DO NOT.

IF 16Gb is actually slower for you than 12Gb, then something else is wrong. But test after real world test has shown that photoshop runs FASTER with 8Gb vs 6Gb. Or 16Gb vs 12Gb. Simple as that.

See:

Graph-Photoshop-diglloydMedium.gif


OMGZ, 4 sticks is quicker than 3 sticks!

4x2Gb > 3x2Gb
8x2Gb > 6x2Gb
 
That's a memory-intensive test and only dependent on the amount of memory you have. I can positively tell you that web pages are loading faster for me on 12GB than 16GB of RAM, and that's easy to see when you use my machine. That is directly tied to the faster Integer speed on the CPU, not the amount of data that can be loaded into RAM at once. Photoshop test would prove faster with 16GB over 12GB because you could load more data into RAM at once time with large files, but your Integer and Floating Point speeds determine the overall speed and user experience of your machine in anything but Photoshop or Lightroom.
 
WardC said:
That's a memory-intensive test and only dependent on the amount of memory you have. I can positively tell you that web pages are loading faster for me on 12GB than 16GB of RAM, and that's easy to see when you use my machine. That is directly tied to the faster Integer speed on the CPU, not the amount of data that can be loaded into RAM at once. Photoshop test would prove faster with 16GB over 12GB because you could load more data into RAM at once time with large files, but your Integer and Floating Point speeds determine the overall speed and user experience of your machine in anything but Photoshop or Lightroom.
Click to expand...

I will have to do my own tests but from my experience more memory bandwidth has made sod all effect on everything apart from synthetic benchmarks, and my god have I done enough of them.
 
a lot of times the mind thinks things are faster ? when doing my LR tests I swore things were way faster then when actual times came in I was shocked they were not !!!


now not saying 3 is not faster than 4 ? it is ? but really it wont be something you notice on web pages etc.. ? I would love to see really solid tests showing this with solid proof cause the proof I have seen is showing a few % max gains ever and that is when its taxed out ?

its like saying one car does 180 and the other 200 but getting to the 180 they are dead even its not till the end that the other pulls ahead ?


again I have not tested this in person but have seen others test and not going to retest since it seems to be a non issue

but that small % when needed is worth it to me so I have 3 8gig sticks ;)
 
Ya I got 20GB in mine right now and I've used it all up a few times. I'm gonna be upgrading pretty soon.
 
Received my 2 x 4GB sticks from OWC yesterday. Ran XBench tests with following memory configurations:

3x1GB = 3GB
2x4GB = 8GB
2x4GB + 1GB = 9GB
2x4GB + 2x1GB = 10GB

Not a significant difference in memory bandwidth or overall system score. More memory helped threading a lot but everything else not so much, about 5-10%.
I left it with 10GB for now.
 
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