Core i5 3.6 GHz vs Core i5 Quad 2.8 GHz

gonzo84

macrumors newbie
Original poster
Jun 14, 2010
11
0
I am sorry if such a thread exists already, i didn't find anything, so......

Im just configuring the iMac I'd like to buy and am wondering about the difference between the Quad Core i5 and the dual Core i5 with 3.6 GHz.

I'm not much of a video or sound editor, not even photos really,, some occasional gaming. I've noticed the 3.6 GHz is Clarkdale in 32 nm while the 2.8 Quad is Lynnfield with 45 nm.

I tend to the Quad, simply because I don't really like something to be maxed out, which i assume is the case in a 3.6 GHz chip.

I am confused and hope u guys can help me make a decision.

Thanks a lot
 

Hellhammer

Moderator emeritus
Dec 10, 2008
22,164
581
Finland
Well, it also depends on whether the game is written for dual core or quad core system. A Quad Core will always be faster than a Dual Core, technically speaking. But a dual 3.6 i5 can be faster in certain applications than a quad 2.8 i5.
Quad i5 goes up to 3.33GHz with Turbo. The CPU is not the bottleneck here, it's the GPU so there won't be huge difference between the games plus all upcoming games support quad core so future wise quad is better investment.
 

alent1234

macrumors 603
Jun 19, 2009
5,661
136
the dual has 4MB cache and the quad has 8MB cache. game performance will be so small you won't notice it.

the sweet spot for this refresh seems to be the higher end 21.5" model. last time it was the lower end 27" which is over priced this time
 

dolphin842

macrumors 65816
Jul 14, 2004
1,168
28
If you're not going to be encoding video or running multiple virtual machines on a regular basis, the dual-core i5 should be fine.

But Eidorian's right... the quad-core will certainly be faster... depends if you want to put out the extra cash though.
 

gonzo84

macrumors newbie
Original poster
Jun 14, 2010
11
0
Thanks guys, you have been a huge help.

21,5'' core i5 would be nice, but i am concerned if the gpu will serve my future needs. 5750 seems to be noticably faster then 5670 i think.

So to sum up, the concensus seems to be Lynnfield Core i5 Quad is better if you want to spend the extra cash. Even though Lynnfield is manufactured in 45 nm? I guess I am overthinking it, anything will be better then my Merom, right? :)

Thanks
 

Hellhammer

Moderator emeritus
Dec 10, 2008
22,164
581
Finland
Thanks guys, you have been a huge help.

21,5'' core i5 would be nice, but i am concerned if the gpu will serve my future needs. 5750 seems to be noticably faster then 5670 i think.

So to sum up, the concensus seems to be Lynnfield Core i5 Quad is better if you want to spend the extra cash. Even though Lynnfield is manufactured in 45 nm? I guess I am overthinking it, anything will be better then my Merom, right? :)

Thanks
The manufacturing process doesn't really speed it up. Lynnfield iMac gets you the better GPU as well
 

stroedel

macrumors newbie
Jul 27, 2010
8
0
tnx for replys...
and what about the i3 versus the "old" Intel Core 2 Duo E7600
cause difference here is 1729 € vs 1499€
 

Hellhammer

Moderator emeritus
Dec 10, 2008
22,164
581
Finland
tnx for replys...
and what about the i3 versus the "old" Intel Core 2 Duo E7600
cause difference here is 1729 € vs 1499€
Depends on what you do. You won't notice much, if any difference if you just browse on the net but if you do something CPU intensive like video encoding, the i3 is better
 

stroedel

macrumors newbie
Jul 27, 2010
8
0
Depends on what you do. You won't notice much, if any difference if you just browse on the net but if you do something CPU intensive like video encoding, the i3 is better
if im not a gamer, and if i only do video encoding once a month..
im thinking on getting dual core + 4 GB extra ram !
pff, they didnt make it easy ...
 

dolphin842

macrumors 65816
Jul 14, 2004
1,168
28
tnx for replys...
and what about the i3 versus the "old" Intel Core 2 Duo E7600
cause difference here is 1729 € vs 1499€
I'll be running some more Handbrake encoding benchmarks once I get to the Apple Store, but here are some results from running it on the last-gen iMacs and current-gen MBP:

[EDIT: scroll down the page for updated benchmarks]
i5 750 (2.6 GHz x 4): 62fps [EDIT: disregard this, I had inferred it from a quad-core i7 reading]
Core 2 Duo (3 GHz x 2): 31fps
i7 (from MBP, 2.6 GHz x 2): 37fps
 

Eidorian

macrumors Penryn
Mar 23, 2005
29,085
290
Indianapolis
I'll be running some more Handbrake encoding benchmarks once I get to the Apple Store, but here are some results from running it on the last-gen iMacs and current-gen MBP:

i5 750 (2.6 GHz x 4): 62fps
Core 2 Duo (3 GHz x 2): 31fps
i7 (from MBP, 2.6 GHz x 2): 37fps
It doesn't sound like Turbo Boost is in action on that Core i5 750.
 

dolphin842

macrumors 65816
Jul 14, 2004
1,168
28
Hmm... I was running Handbrake in the same way on each machine (High Profile x264, RF 28). The quad-core i7 got ~67fps. Are the other figures in line with what you'd expect?
 

freiheit

macrumors 6502a
Jul 20, 2004
642
90
California
Looking forward to your new i5 / old i5 numbers in Handbrake

I'll be running some more Handbrake encoding benchmarks once I get to the Apple Store, but here are some results from running it on the last-gen iMacs and current-gen MBP:

i5 750 (2.6 GHz x 4): 62fps
Core 2 Duo (3 GHz x 2): 31fps
i7 (from MBP, 2.6 GHz x 2): 37fps
It's a shame for them to call that overpriced dual-core an i7. It's a crying shame and gives the i7 a bad name. Looking forward to your reports on the new iMacs, especially the dual-core i5 versus the quad-core i5 since both technically provide 4 threads. I suspect real cores will always beat virtual ones, but over time virtualization/hyperthreading should become more refined and maybe the line will blur.
 

RAM3Zero

macrumors newbie
May 27, 2010
10
0
Just ordered!

As a direct result of this thread, I finally placed my order for a 27" quad i5 (with trackpad, I couldn't resist). Was considering going low-end but knew in the end I wouldn't be satisfied. I've been itching to switch over to mac for a really long time now and finally placing the order is quite freeing.

Thanks to Hellhammer, TMRaven and Eidorian (plus others) for their solid input over the past 6 months. I've been following your posts regularly and you've answered my unasked questions and provided great data. Should arrive between August 3rd-10th in Canada, will keep you posted.

R.
 

dolphin842

macrumors 65816
Jul 14, 2004
1,168
28
Alright, just got back from the Apple Store. There weren't any i5 3.6GHz (dual-core) or quad-core i7's on display, but I got stats on the rest. Here they are along with all my other data:

Handbrake x264 test (High Profile, 28 RF, 720x480 DV source file @ 60fps, anamorphic loose w/ 40px auto-cropping on left and right):

13fps: 1.83 Core Duo (original intel iMac, my current machine:rolleyes:)
25fps: 2.6 Core 2 Duo (Mac Mini Server)
31fps: 3.06 Core 2 Duo
37fps: 2.66 i7 (dual-core, MacBook Pro)
41fps: 3.06 Core i3 (dual-core)
43fps: 3.2 Core i3 (dual-core)
65fps: 2.8 Core i5 (quad-core)
67fps: 2.8 Core i7 (quad-core, 2009 model)

A few notes for this particular workflow:
- The move from Core 2 --> i3 yields about a 32% performance increase at identical speeds for the dual-cores. What a difference an architecture can make:cool:.
- The flip side of the previous point: Whereas moving from to 2 to 4 cores yielded an essentially linear performance increase in last year's models (~100% when the jump was from a core 2 to a core i5), this year the extra cores only get you a ~50% increase in performance.
- The speed bump from 3.06 i3 --> 3.2 i3 is rather minimal; in this case, you'll only want to pick the faster model if you want the newer ATI graphics and/or the extra 500GB of internal storage. For single-threaded applications, I believe the 3.2 i3 has turbo boost, which may make a bigger difference.
- Hyperthreading (quad-core i5 vs. i7) yields only a 3% speed increase, likely because x264 is multithreaded and maxing out all physical cores, leaving little downtime for hyperthreading to be of use.
 

freiheit

macrumors 6502a
Jul 20, 2004
642
90
California
You are wonderful!

Alright, just got back from the Apple Store. There weren't any i5 3.6GHz (dual-core) or quad-core i7's on display, but I got stats on the rest. Here they are along with all my other data:
You are wonderful! Thank you so much for posting this. Does the Apple store seriously let you go in and put your own data on their systems to try stuff out? I mean, you had to have installed Handbrake and attached a drive with your data and stuff. What DON'T they let you do?

It's too bad you didn't get to benchmark the dual-core i5. I'd love to see how it compares to the quad-core and how much you really get over the i3 running 400MHz slower. I would prefer to buy a quad-core, but the 27" screen is far too big and high resolution for me, so the top 21.5" is where I'd be buying unless the 27" with i5 shows a significant performance boost.
 

dolphin842

macrumors 65816
Jul 14, 2004
1,168
28
You are wonderful! Thank you so much for posting this.
No problem... I'm in the market for a new Mac myself so I figured I'd share what research I've done so far :).

Does the Apple store seriously let you go in and put your own data on their systems to try stuff out? I mean, you had to have installed Handbrake and attached a drive with your data and stuff. What DON'T they let you do?
Yeah, the retail stores let you mess around with the Macs quite a bit. I've not had any employees ask what I was doing, though one time they did quickly reboot the machine after I left :rolleyes: (I assume it has a default disk image that it reverts to). As for file transport, Handbrake.app and my test file fit on a 1GB flash drive, so it's easy to just hook up and drag both to the desktop.

It's too bad you didn't get to benchmark the dual-core i5. I'd love to see how it compares to the quad-core and how much you really get over the i3 running 400MHz slower. I would prefer to buy a quad-core, but the 27" screen is far too big and high resolution for me, so the top 21.5" is where I'd be buying unless the 27" with i5 shows a significant performance boost.
My guess is that the performance increase going to the 3.6 i5 will be pretty linear. Both cores are taxed with x264 encoding, so even if the turbo boost is more substantial on the i5, there won't be much opportunity to use it (similar to hyperthreading's limited usefulness in this scenario).

So for the 3.6 i5 you'd probably be in the 48fps range or thereabouts. If that's the case, then the move to quad-core would give a performance increase in the neighborhood of 35%. As I mentioned above, the speed bump going from dual-core-->quad-core is less pronounced this time around due to the lower-end iMacs finally getting the new i-series architecture. So unless you plan on encoding videos fairly regularly, the extra cost of the 27" might not be worth it.
 

Will : Hi !

macrumors member
Apr 1, 2006
35
0
Hyperthreading (quad-core i5 vs. i7) yields only a 3% speed increase, likely because x264 is multithreaded and maxing out all physical cores, leaving little downtime for hyperthreading to be of use.
HandBrake's High Profile preset enables 2 poorly-threaded filters (decomb, and more importantly detelecine) by default.

Edit: Also, DV at 60 fps? Are you sure it's not 480i60 (60 fields per second)? That's likely causing some more time spent in the filters vs. actually encoding in x264.
 
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