Advice wanted: Mac Mini, 4GB/3.3GB, and dual channel

We have some pretty sharp computer folks here so I thought I would ask.

My primary workstation is now a Mac Mini with 2GB of RAM. I hit the RAM pretty hard: Adobe Lightroom, PS Elements 4, VMWare Fusion running my legacy Win32 apps, so the little Mini really gets quite a thrashing. I could definitely use more RAM. The thing I liked about PC hardware was that I could customize it, well, the Mini isn't quite as customizable. No bashing intended. I love the Mini and that is why I ask these questions. If I hated it, I would simply change back and this post wouldn't even exist

OK, onto the questions.

I'm planning an upgrade for it now that I've learned the Mini can actually handle 2x2GB DIMMs. "Handle 4GB" - well, it recognizes 2x2GB DIMMs but due to the addressing limitations of the Intel 945 chipset, it cannot use all of it. So Apple has never provided 'official' support for 4GB. Realistically you are limited to 3.3GB of useable RAM once all is said and done. 2GB -> 3.3GB would be an increase of 1.3GB for me and that is QUITE a lot of extra memory IMO.

I'm debating two approaches since I have 2x1GB in it right now. Approach 1 is to use 1 x 2GB, 1 x 1GB for total of 3GB of RAM. Problem is, I lose dual channel memory. It'll work but the DIMMs won't be interleaved for improved memory bandwidth.

Approach 2 is to simply use 2x2GB and 'lose' the 700MB of inaccessible memory but retain dualchannel memory bandwidth. Of course, I would have to pony up more $$ for the second DIMM.

Is it worthwhile to go with 2x2GB and pay the extra to retain dual channel? How much performance, in practical terms, am I expected to lose?


I could buy an iMac I suppose, but I am not really that keen on spending so much money at this time..

I hope Apple releases a breadbox sized souped up Mac Mini. Really the Shuttle XPC is perfect for my needs. Problem is, OSX doesn't run on generic hardware and the Shuttle XPC isn't exactly from Apple

KevinL said:

My primary workstation is now a Mac Mini with 2GB of RAM....Is it worthwhile to go with 2x2GB and pay the extra to retain dual channel? How much performance, in practical terms, am I expected to lose?

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I don't know that you'll notice any real difference in performance between interleaved and non-interleaved memory. The increase/decrease in speed you'll see will actually be more dependent on the chipset you're using ( and how it manages that installed memory ), rather than anything based on the theoretical gains expected from interleaving itself. And when it comes to the 945PM intel chipset, some ad-hoc testing seems to indicate that it is pretty much relegated to zero noticeable gains between interleaved and non-interleaved memory configs.

As a Mac user, one of your best resources for real world performance testing data like this is at a site called Bare Feats. They place myriads of configurations through real-world, quantitative testing all while using the apps & configurations that an end-user would be most likely interested in running. An excerpt from their tests of a MacBook Pro running the same chipset as your Mini showed no performance gains from interleaving, despite what the theoretical gains say they should be:



And seeing as that you can 'try it out' for the very reasonable cost of admission of $51 bucks plus shipping over at OWC, you potentially have very little to lose and a whole Gig to gain.

Mednanu said:

I don't know that you'll notice any real difference in performance between interleaved and non-interleaved memory. The increase/decrease in speed you'll see will actually be more dependent on the chipset you're using ( and how it manages that installed memory ), rather than anything based on the theoretical gains expected from interleaving itself. And when it comes to the 945PM intel chipset, some ad-hoc testing seems to indicate that it is pretty much relegated to zero noticeable gains between interleaved and non-interleaved memory configs.

As a Mac user, one of your best resources for real world performance testing data like this is at a site called Bare Feats. They place myriads of configurations through real-world, quantitative testing all while using the apps & configurations that an end-user would be most likely interested in running. An excerpt from their tests of a MacBook Pro running the same chipset as your Mini showed no performance gains from interleaving, despite what the theoretical gains say they should be:

"...Of more concern to "speed freaks" is the potential loss of interleaving when you install unmatched pairs (as in the Apple factory's 1GB + 2GB config). Based on our testing, the MacBook Pro goes just as fast with unmatched memory as it does with matched. And apps like Aperture and Photoshop can certainly use the extra memory afforded by the 3GB config." - Quoted directly from Bare Feats' - Quick Takes article​

And seeing as that you can 'try it out' for the very reasonable cost of admission of $51 bucks plus shipping over at OWC, you potentially have very little to lose and a whole Gig to gain.

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Awesome, thanks dude!!

Part of the problem with the Net is that while there is a great deal of useful info out there, it's hard to find while stumbling around using basic keyword searches. Thanks for pointing it out for me and summarizing it so well.

My own intuition and previous work with PC's over the past decade told me that even if I did take a small performance hit (assuming there was one) on the interleaving, "RAM vs HD - RAM always wins by orders of magnitude" so go ahead and stuff the extra GB into it. You can never have too much RAM. I'd put 16GB in the box if I could! (just that the MacPro's a bit too expensive for my admittedly cheap taste in computers )

I've got a good source for DIMM's locally so I will go down and grab one. Comes to the same price, and instant gratification. Good thing I found my old putty knife too.. I have one from the time I last needed to carve up my G4 Mini..

http://eshop.macsales.com/shop/Memory_Benchmark/Apple_MacBook/

"NOTE: A 4.0GB (2GB x 2 Pair) configuration was also tested by 'popular demand'. Although the Core 2 Duo Macs are limited to 3.0GB addressed, the 4GB Set (2GB x 2 Pair) does appear enable 128 Bit addressing. While there does seem to be a small performance benefit gained with the 4.0GB vs. 3.0GB config, we'd recommend sticking with 3.0GBs max (in Core 2 Duos) unless you absolutely are seeking every last trickle of performance boost possible."


Cool (found that article linked from the real world speed tests)

I don't chase percentage points any longer. Good news to know that my Mini can take another GB!