Mac Pro 2008 vs. iMac 2011 for Logic



I'm currently running Logic Pro (8, but will be upgrading to 9 with the
new system) on a 2006 MacBook Pro with 2GB of RAM and a 350GB hybrid
disk. I run into the dreaded system overload with some regularity. I
don't run very high track counts and do very little recording, but I
tend to use a lot of softsynths (mostly from the NI Komplete suite) and
use a very large array of effect plugins per track.

I've been saving up to replace this machine, and was targeting the
newly-released 2011 iMac 27" with the 3.4GHz quad-core i7 Sandy Bridge
processor, 4GB of RAM (that I was going to upgrade to 12GB after the
fact -- the system maxes out at 16GB), the 256GB SSD + 1TB HD disk
configuration and the 2GB GDDR5 Radeon HD 6970M. With the AppleCare,
this clocks in at $3098 + tax.

However, it's recently come to my attention that a local shop is selling
a gently used 2008 Mac Pro. It has two 2.8GHz quad-core Nehalem Xeon
processors (8 cores total), 4GB of RAM (maxes at 32GB), a 320GB hard
disk, and an NVidia 8800GT with 512GB RAM. They'll warranty it for 90
days and you can pay extra to extend the warranty if you like, although
it'll be their warranty rather than AppleCare. They want $1699 + tax.

Among my geekier-than-me friends, there's been a big debate about the
CPUs in these two machines. The iMac's Sandy Bridge architecture
supports SVX instead of SSE, which apparently will, once apps are
updated to support it, allow it to process eight instructions per cycle
rather than four, according to them. Given that it's already clocked
faster than the Xeons in the Mac Pro, that would make it noticeably
faster CPU-wise. The rest of the Mac Pro's architecture is slower as
well -- the memory bus isn't as fast, the 8800GT is about half the
performance of the 6970M, etc. However, the Mac Pro offers more
expandability -- I could add a RAID card, I could have several internal
disks, I can upgrade the video card, etc. And if Logic Pro doesn't
support SVX, then I expect that having twice as many cores at a slightly
slower speed might be a CPU win.

But the difference in price is also a big factor -- with that much less
money I could perform a lot of ugprades (note that I'd have to eat away
some of that buying a monitor, but you can get a 27" LCD of good enough
quality for me for $300, and getting a disk system comparable to the one
I was speccing for the iMac would take away more of that, but I could do
this flexibly over time). I mean, at $1699, I wouldn't be particularly
upset if I had to upgrade it after only say three years, whereas at
$3100, I'd want the iMac to last me a good five years, much as my
MacBook Pro did.

My only real bottleneck is Logic Pro, though. This is going to be my
studio machine. I mostly game on the Playstation 3, and I have an iPad
that is fine for my needs for travel and surfing. So I'm wondering if
any of you have any thoughts or real-world experience between these two
machines as they specifically pertain to Logic Pro, and if anyone knows
what the status of this SVX issue is with Logic Pro -- if it's something
that I should expect to see coming down or that's even already there, or
if it's even relevant to Logic Pro's architecture, or if having twice as
many cores will still be better when running a ton of plugins.

[Note: I did track down one benchmark that compared both machines -- the Geekbench puts the iMac quad-i7 3.4GHz at about 12,000 in 64-bit Mac OS X mode, with the Mac Pro eight-core 2.8GHz Nehalem Xeon coming in around 8,000 on the same mode. I'm not sure precisely what that benchmark tests for and how well it maps onto Logic performance, though.]
I'd say the iMac with the Sandy Bridge CPU and 12 gig of ram (so the cpu can work in triple memory mode, a faster way to access memory) would be my choice, based on the fact the the older machine was/is 3 years old, and 3 or 4 generations of CPU's back.

You are right about the Mac Pro having some advantages, especially when it comes to upgrades, but the question I wonder is this: how many channels do you want to record and playback at any one time?

A new Duet would be a smoking 2 in 4 out solution, using usb2, and once the new thunder bolt ports come online with raid solutions for disc access, you will be smoking fast.

Also, the new apple monitors blow the doors off any $300 monitor I've seen, they are really beautiful.

So there's my suggestion...
Thank you for the input! I believe that after a lot of research, that's the decision I'm coming to myself. I've been saving for the iMac for almost a year now, so although it's tempting to go with the Mac Pro at least in part to have all that extra money available for software upgrades and the like, I think that I'll be left always second-guessing the choice and feeling like it would have been better to wait the couple of months to get the iMac. It does seem to be the case that it will in the long run be much faster, and I've budgeted to get the SSD+1TB configuration with the upgraded video card and the 3.4GHz i7.

Does the specific configuration of the RAM matter in terms of triple memory mode? My plan was to get the base 4GB from Apple, which comes as two 2GB modules, and then buy an 8GB (two 4GB modules) kit from a third party (for a fraction of the money), to bring it up to 12GB as 2+2+4+4. Does that work for what you're talking about? It's actually not much more to just top it up to 16GB from the get-go so long as you're buying from a non-Apple source, and the RAM is the one part that's easily user-upgradeable on the iMac.

In terms of tracks, my track counts at the moment are not very high. Most of my projects, by the time they're done, have 12-16 tracks at the most. What does seem to be pushing the envelope on my current system (2006 MacBook Pro) is a high number of plugins per track. I currently freeze tracks that I'm not working on *right now* to get around that, but constantly freezing and unfreezing gets tedious at times.
Triple memory is something that makes a difference in the current Mac Pro's, but as I think of it, the Sandy Bridge systems don't do that anyways (they are only dual mode, not such a bad thing actually).

As for plug-ins, it really depends what one if using as related to performance. Some take a boatload of cpu, some very little.
Don´t know the new imac but I have the MacbookPro from this year with the quad-core i7 processor with 8GB Ram. It really rocks!
Only one example:
Last gig I was using a Mainstage Project with about 30 Patches with many Samplers and Organs and Pianos for Life playing AND made a 16 Channel Live Recording at the same time with logic. The Mainstage goes over Saffire pro Firewire interface and Logic uses the Presonus Studio Life 1642 (also Firewire) Firewire Routing: Macbook Pro - Presonus - Saffire. The only thing was, that the Saffire needed external power supply.
Greetings Uwe