Multitasking Performance - The Quad Core Advantage

We're almost at the end of the review and so far we've hardly shown any performance benefit thanks to quad cores; just about all of the benchmarks we've presented here today could be duplicated if you only had a single Xeon in the Mac Pro instead of two.

It seems that many multithreaded applications are specifically targeted at dual core systems, and scaling above and beyond two simultaneous (and CPU intensive) threads just isn't where it needs to be for four cores to make a big difference. With the trend in CPU architectures being to significantly ramp up the number of cores, software will follow, but for now truly taking advantage of four cores is much like the early days of dual core processors: you either need an application that is specifically designed to scale to four cores (e.g. CineBench/3D rendering), or you need to be a heavy multitasker.

We've already shown what the former can bring, but what about the latter? How much of a benefit do you gain from having four cores at your disposal? To find out we combined two of our benchmarks - the multithreaded CineBench 9.5 test and our Quicktime H.264 encoding test. We started the H.264 encode first and then started the CineBench rendering test; we reported scores for both.

Multitasking Performance: CineBench 9.5

With only two cores, the CineBench results between the PowerMac G5 2.5GHz and the Mac Pro 2.66GHz are reasonably close, with the Mac Pro only holding a < 6% advantage. The H.264 encoding performance is a bit more favorable to the Mac Pro, with the dual core 2.66GHz solution outperforming the G5 by 14%.

Multitasking Performance: Quicktime H.264

Enabling the remaining two cores on the Mac Pro however really changes the picture; the four core Mac Pro is 1.6x faster than the hypothetical two core version in CineBench and at the same time is 17% faster in the H.264 encoding test.

It's not too surprising to expect that the more CPU intensive tasks you run simultaneously, the more of a performance improvement you'll see with four cores vs. two. It's just like the early days of dual core CPUs; just wait until Apple throws two quad core Clovertowns in the Mac Pro, then we'll really start running out of things to do with them.

Professional Application Performance with Final Cut Pro, Xcode and CineBench Rosetta Performance (or lack thereof)
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  • rockinphotog - Saturday, August 19, 2006 - link

    AS a matter of fact, I often use my apple keyboard for my digital camera, printer, syncing my treo and even my wacom tablet.
  • aaronlyon - Friday, August 18, 2006 - link

    In next week's article, please evaluate Parallels Workstation for running Windows apps simultaneously with Mac OS. If this works smoothly, why not use Windows versions of Adobe Photoshop and Illustrator? That would be a good solution while waiting for Universal Binary updates.
  • Zebo - Friday, August 18, 2006 - link

    Great pics and article Anand.

    What a deal for such a clean system. They don't build PCs that pretty and this is the best yet from Apple's industrial design squad. I definity want one but don't need four cores.

    Can I run Windows fully with this machine? Or maybe I should wait until a single processor (dual core) version comes. If Apple sells $1500 Conroe boxes and it ran windows they counld'nt keep them in stock.
  • plinden - Friday, August 18, 2006 - link

    quote:

    Can I run Windows fully with this machine?


    There's an issue with the speed of SATA hard drives, as Anand mentions here: http://www.anandtech.com/weblog/default.aspx#287">http://www.anandtech.com/weblog/default.aspx#287

    It will probably be fixed eventually but if you're relying on this to run Windows, you should wait.
  • FutureMedia - Thursday, August 17, 2006 - link

    You are not comparing the Quad G5 Rear Ports to the Mac Pro Rear Ports. Quad G5 has 3 USB 2 ports as well as 2 Gigabyte Ethernet ports just like the Mac Pro. IE the Quad G5 rear set of ports is IDENTICAL to the Mac Pro rear set - just laid out differently. Only the front adds a fifth USB 2 and second FW800 port not on the Quad G5 which is the same layout as what you show from OLDER not last generation October 2005 PowerMac G5s.

    Moreover I was looking forward to a Quad G5 comparison with the 2GHz and 2.66 GHz Mac Pros. That is what I want to know. Especially Is even the 2GHz Mac Pro faster than the Quad G5? Is the problem that you don't have a Quad G5 in house to compare it to? I am so bummed out that you didn't compare Mac Pro two bottom speeds with the Quad G5. Please can you do it after next week? I would really appreciate it. Thanks.
  • PhilG5 - Friday, August 18, 2006 - link

    Thank you so much for pointing that out! In fact, Anandtech uses mid-2004 PowerMac G5 (still using AGP graphics and DDR-400 memory!) and doesn't take into account the whole "late 2005" series (which first supported DDR2, PCI-E and had the "Antares" PPC970 core). If you look at Barefeats benchmark results ( http://barefeats.com/quad06.html">http://barefeats.com/quad06.html ) the Quad G5 still seems to be pretty much competitive with the new Mac Pros.
  • Anand Lal Shimpi - Friday, August 18, 2006 - link

    We did not have a Quad G5 on hand, however the performance results woult not have been that different. The benchmarks that show little or no scaling between the Dual and Quad Mac Pros would show the same scaling between dual and quad G5s (which were most of the benchmarks). None of our tests were GPU bound, so difference in graphics interfaces should also minimally impact performance. The only real variable that could have changed things is DDR2, however seeing as how none of the DDR-DDR2 transitions we've seen on the PC side have done anything for performance, hopes aren't too high for a tremendous impact on G5 performance.

    Take care,
    Anand
  • Konq - Thursday, August 17, 2006 - link

    Anand - I think something is wrong with the 2 vs. 4 core Xcode test. As with gcc, you can tell it to compile with as many threads as you like. This will compile 4 source files at the same time for instance on 4 cores (multitasking). Perhaps the code was too small to really see a difference, or the environment was not set right?
  • Konq - Saturday, August 19, 2006 - link

    OK, now another interesting 4-core note: MacWorld did a test with iTunes and a quad core, 2.5 Ghz G5 beat a dual-core, 2.7 Ghz G5 system when converting 45 minutes of AAC files to mp3. Maybe this was due to having multiple files to work on? AAC->mp3 vs. Wave->mp3?

    One thing I am interested in now: An article that covers how to get the most out of 4-core systems. Which software benefits and how. Since 4-core processors are coming out soon, this will be needed in purchasing decisions.
  • Konq - Friday, August 18, 2006 - link

    I verified on the Apple Xcode users list that Xcode can indeed take advantage of every core. You might want to modify the test you do and configuration if needed.

    Great article btw. I enjoy reading reviews from you that can be counted on for true pro's and con's instead of overly rosey approach from fan sites.

    In spite of "horrid memory system", it sounds like the system kicks butt! One is in my future...

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