Comparison between similar spec iMac and MP

[JimmyDreams]

I know we don't know yet what the MP refresh will be exactly, but...

Would there be any performance difference between a 3.4GHz quad core i7 with 16gig RAM versus a very similarly spec'ed new MP? The iMac CPU is basically a laptop version, but since the MP would undoubtedly be afforded more cooling, etc., I'm wondering where the differences would be?? And would those differences be enough to justify the cost?

I'm seriously considering a loaded iMac with an SSD vs waiting for the MP refresh because, quite frankly, the $2K + price difference is staggering. Besides, I'm upgrading from a 2007 2.8GHz Core Duo iMac, and the new Sandy-bridge architecture, increased cache (and cache speed), increased RAM, etc., would make a new iMac seem like a rocket.

I'm thinking that the TB port on a new iMac would afford enough expandability (that the old iMacs lacked) that it begins to approach the performance/expandability of a MP.

Am I wrong in my thinking??? You guys are the Mac gurus....I'd like to hear your thoughts on the matter.

 

[CaoCao]

The CPU in the iMac is a desktop CPU.

 

[Hellhammer]

Mac Pro will most likely sport a faster GPU. Otherwise it should be as fast as similar Mac Pro.

 

[JimmyDreams]

The CPU in the iMac is a desktop CPU.

I know that. But is a laptop version and desktop version of a similar CPU similar in performance, or is the desktop going to be much faster because it can have a more robust motherboard, size, heatsink, etc.?

I guess therein lies my real question: how much of a handicap is/are the iMacs with their limited space, heatsinks, etc., when compared to a similar spec'd MP? Is future expandability the biggest benefit or the fact that MP's can have multiple CPUs etc., or is the gap between iMacs and MPs closing so narrowly that it takes a real power-user to need a MP?

 

[Hellhammer]

I know that. But is a laptop version and desktop version of a similar CPU similar in performance, or is the desktop going to be much faster because it can have a more robust motherboard, size, heatsink, etc.?

I guess therein lies my real question: how much of a handicap is/are the iMacs with their limited space, heatsinks, etc., when compared to a similar spec'd MP? Is future expandability the biggest benefit or the fact that MP's can have multiple CPUs etc., or is the gap between iMacs and MPs closing so narrowly that it takes a real power-user to need a MP?

iMac's cooling is good enough to dissipate all heat when the CPU is at 100% load. The cooling won't make Mac Pro any faster, it's not like the iMac runs too hot.

Mac Pro can't take multiple CPUs unless you buy one with two CPUs. The SP Mac Pros only have one socket.

 

[jonnymo5]

It comes down to how you use it. If you are an average user then the iMac is a no brainer. It has become a much better desktop recently. If you have to ask then you should strongly consider the iMac.

Get the Pro if you know you:
1. Will be upgrading, cpu, graphics
2. Need additional internal disks
3. Want to run a lot of monitors
4. Run the computer maxed out for long periods of time

The iMac can get hot. CPUs get down-clocked when they get hot enough and impurities will cause issues with components. If you are going to use the machine as a server or for intense tasks over a long time then you want the workstation grade hardware in the Mac Pro. The value there is reliability and longevity, you won't get better performance.

 

[supercooled]

The iMacs have come a long way from the heady days when it was just a utilitarian desktop with embarrassingly shared resources with their mobile computers. If I had to do it all over again, I would get the iMac instead of the MP which doesn't offer that much more besides minimal expansion capabilities. Practically speaking, how many MP owners will be upgrading their cpu? Storage needs can be met with NAS or other forms of upgrades. What's the current iMacs memory threshold; 16GB? More than enough for even hobbyists/enthusiasts editors.

If I could get a decent resale for my MP2008, I would get the 27" i3 iMacs. It's more computer than most people need, imo.

 

[JimmyDreams]

It comes down to how you use it. If you are an average user then the iMac is a no brainer. It has become a much better desktop recently. If you have to ask then you should strongly consider the iMac.

Get the Pro if you know you:
1. Will be upgrading, cpu, graphics
2. Need additional internal disks
3. Want to run a lot of monitors
4. Run the computer maxed out for long periods of time

The iMac can get hot. CPUs get down-clocked when they get hot enough and impurities will cause issues with components. If you are going to use the machine as a server or for intense tasks over a long time then you want the workstation grade hardware in the Mac Pro. The value there is reliability and longevity, you won't get better performance.

Thanks for the synopsis! From what I understand, the TB connector on an iMac would enable options 2 and 3 above for a TB equiped iMac? So the MP comes down to really upgrading CPUs or graphics, and workload....occasionally using Final Cut or CS5 probably wouldn't require a MP??? Which leads me back to iMac......

 

[jonnymo5]

Occasional and even regular use of FCP and CS5 should be great on the iMac.

 

[deconstruct60]

From what I understand, the TB connector on an iMac would enable options 2 and 3 above for a TB equiped iMac?

Option 2, technically no. TB allows you to add an external drive that can same performance as an internal drive. However, it won't be inside the box. Some people have space and/or drive security issues. Inside the box means don't need more security for yet another external box. Nor power.

That isn't necessarily a minus since there are upside to putting a drive array outside the box if external drives are OK.


Option 3, depends upon what "a lot" is. For some that is more than 4. For others more than 2 . Driving more than 2 monitors has as much to do with TB as it has to do with the GPU and associated video buffer size ( VRAM or shared space). The TB standard says an implementation can get away with just one DisplayPort lane. However, even if there are two on the controller chip doesn't mean the GPU can drive 3+ at the same time.

Some CS5 programs use available VRAM to speed things up. Most of the iMacs don't have large bufffers. (some do, most don't). They are big enough for a monitor but if are pushing 3 and doing lots of VRAM for each one the Mac Pro could be better.

 

[Hellhammer]

However, even if there are two on the controller chip doesn't mean the GPU can drive 3+ at the same time.

All GPUs in current iMacs support up to six displays.

 

[deconstruct60]

All GPUs in current iMacs support up to six displays.

Only if they are hooked up to run six.

".... Also, at least 3 simultaneous, active display outputs, including one DisplayPort™ connector are required to support AMD Eyefinity technology. ..."
http://www.amd.com/us/products/tech...ology/how-to/Pages/faqs.aspx#products-support

For 4 monitors conceptually it can be done by 2 display ports, but that's DP 1.2

However if you do a "set up" with "Productivity -> Advanced " the number of recommended cards is smaller:

http://www.amd.com/us/products/technologies/amd-eyefinity-technology/how-to/Pages/set-up.aspx

 

[Elisha]

Even if the cpus are the same, the chipset on the motherboards are different.
That makes a difference as well if you ask me!

 

[Hellhammer]

Only if they are hooked up to run six.

".... Also, at least 3 simultaneous, active display outputs, including one DisplayPort™ connector are required to support AMD Eyefinity technology. ..."
http://www.amd.com/us/products/tech...ology/how-to/Pages/faqs.aspx#products-support

For 4 monitors conceptually it can be done by 2 display ports, but that's DP 1.2

However if you do a "set up" with "Productivity -> Advanced " the number of recommended cards is smaller:

http://www.amd.com/us/products/technologies/amd-eyefinity-technology/how-to/Pages/set-up.aspx

Thunderbolt uses DP 1.1a which also supports daisy-chaining. Six is probably too much given the bandwidth limitations but I can't see why four external monitors along with the internal one wouldn't work. After all, two 30" ACDs work fine.

 

[deconstruct60]

Thunderbolt uses DP 1.1a which also supports daisy-chaining.

The display port folks don't seem to think so.

"... Q: When will DisplayPort support 'daisy-chaining' of Displays ? DisplayPort specification version?

A: The next version of DisplayPort, DisplayPort v1.2, supports monitor daisy chaining.
... "
http://www.displayport.org/consumer/?q=content/faq


I think 1.1a allows different video signals do go down the different lanes available. So the card can send the signal to a "splitter"/"hub" which then sends them down separate cables to different monitors.

Singals that haven't already been multiplexed by DP are going to be much easier for Thunderbolt to route over the TB topology.

Six is probably too much given the bandwidth limitations but I can't see why

It is not just bandwidth. it is also how much video memory the graphics require. 5 monitors running Text Edit ... sure that works.

 

[Hellhammer]

The display port folks don't seem to think so.

"... Q: When will DisplayPort support 'daisy-chaining' of Displays ? DisplayPort specification version?

A: The next version of DisplayPort, DisplayPort v1.2, supports monitor daisy chaining.
... "
http://www.displayport.org/consumer/?q=content/faq


I think 1.1a allows different video signals do go down the different lanes available. So the card can send the signal to a "splitter"/"hub" which then sends them down separate cables to different monitors.

Singals that haven't already been multiplexed by DP are going to be much easier for Thunderbolt to route over the TB topology.

Yeah, looks like that. My mistake then but to be honest, I don't see what the real difference is since you can run two monitors off of one TB port.

It is not just bandwidth. it is also how much video memory the graphics require. 5 monitors running Text Edit ... sure that works.

Two 30" ACDs have 8 192 000 pixels and have been proven to work with 27" iMac. Four 1080p monitors have 8 294 400 pixels, so only slightly more. In theory, shouldn't four 1080p displays work as well since the pixel counts are almost equal? My knowledge ends where you would have to calculate the amount of VRAM you need to drive those pixels but I think at least the 2GB AMD 6970M should be able to do that.

Of course, I'm not talking about gaming or stuff. The 6970M is poor enough at 1440p Let alone what tripling the pixels would cause