SPECIAL MEMORY AND DRIVES FOR THE 8-core?
#How many processors in a 6 core mac pro how to#
If you are using After Effects CS3 (or any app like it that knows how to use all 8 cores effectively), the 8-core is worth the extra money, in our opinion.Īnd if you perform multiple tasks within an application (like our QuickTime simultaneous conversion test above) or have multiple apps active (like in our Multi-Processing page), then you are a candidate for an 8-core Mac Pro.
#How many processors in a 6 core mac pro pro#
In spite of the limitations posed by the memory bus and OS X "Tiger's" handling of core swapping, there are things that the 8-core Mac Pro does signficantly faster than the 4-core Mac Pro. OUR CONCLUSION FROM TEST RESULTS ON THIS PAGE (and others) On the other hand, there are scenarios where the 8-core Mac Pro will be able to show its multi-threading muscle, as exemplified by the QuickTime graph above. When this thread/core shift happens repeatedly, it makes the cache ineffective and floods the memory bus with activity." (Though put forth by an anonymous BF reader, this analysis has been confirmed by Lloyd Chambers where he discussed "core swapping" on his latest blog entries regarding the 8-core Mac Pro.) Since Intel quad-cores are two Core 2 Duos "duct-taped" together, the problem is worse than it would otherwise have been. When a thread moves to a different core-group, the cache has to be reloaded on the new core.
the problem is that the OS does not know that it should keep a thread on the SAME core instead of swapping it around to any one of the 8-cores. "Yes, the memory bus is weak, but the biggest problem is that OS 10.4 (Tiger) does not know how to deal with so many cores. But if your task has to do a lot of interaction with memory, the advantage drops almost to nothing - as we saw with Photoshop CS3 and Aperture. That says that if the task is pure CPU, the 8-core is twice as fast as the 4-core. Its aggregate rate was 1204MB/sec (versus the 4-core's 601MB/s). We did run the "test-compute-speed" with digLloydTools (DLT) on the 8-core. By comparison, a 6-drive hard disk RAID array can easily perform at over 400MB/sec!" That’s a measly 700MB/sec per core on a quad-core machine, and only 350MB/sec per core on an octa-core machine. Memory copy speed is at best 2.9GB/sec on the Mac Pro, in spite of Apple’s highly misleading claims of 21.3 GB/sec (“maximum processor bandwidth of up to 21.3 GB/s”-bandwidth is a bit more than double the memory copy speed). It’s already a limiting factor with the current quad-core 3.0 GHz Mac Pro. He wrote, "Memory bandwidth is inadequate for 8-cores. Our friend, Lloyd Chambers, thinks there's a memory bus bottleneck for the 8-core, which he discussed back in March on his blog. Multi-Processing (Simultaneous rendering by Final Cut Pro, Motion, iDVD, and Photoshop CS3)ģD Gaming (Quake 4, Doom 3, Unreal Tournament 2004, Halo, World of Warcraft, Prey) using three different graphics cards Special Report on After Effects CS3 running on the Mac Pros, G5 Quad, and MacBook Pro.
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