Mac vs PC: bus bottleneck in Mac?

Question

I am a long time Mac user considering an upgrade to a Mac Pro for photography and soon for video and gaming. A photographer friend familiar with both Macs and PCs told me that I should consider the PC option for resource intensive applications as Macs have a bus bandwidth limitation that PCs do not. I'm waiting for him to get back from vacation to discuss this in more depth but in the meantime thought I'd try to get some authoritative insights here. Relative to PCs, is there any bottleneck in Mac hardware?
Thanks in advance for any comments.

Answer 1

Most of the time, this type of comments from your friend can be chalked up to comparing older Mac technology with new PC technology. Here is an example, and one that keeps rearing its ugly head from time to to time.
In 2006 Apple introduced the Mac Pro the first of the Intel based workstations. One of the choices Apple made was to us FB-Dimm in its memory architecture. FB (fully Buffered) memory increases both reliability and memory density, but because it requires an intermediary memory buffer between the memory and memory controller, it can have a lower top memory bandwidth then more conventional memory designs because of the increase latency caused by the memory buffer system.
The trade off for memory reliability, automatic error correction with no system overhead was probably the right choice for a workstation class system. But boy did the PC folks love to use memory bandwidth benchmarks to show how inferior the Mac Pro was for playing games.
Over the years, Apple has both improved the memory bandwidth, and changed to new memory architectures that provide a nice increase in memory performance. However, the old Macs are slow because of poor memory performance is still often heard, though it is no longer true, actually it was never true it was just dependent on which type of tests you want to use for your benchmarks.
So next time someone tells you a Mac has bus bandwidth limitations, ask them for specifics. Which Mac model vs which PC model, and just what benchmarks were used and what were they testing for.
Tom