What iMac configuration should I buy?

I have been running SketchUp on a 2011 iMac with a 3.06GHz Core i3, 12GB of RAM and only 256MB of graphics memory, and it is just not enough anymore. I am planning on purchasing a new 21" iMac with 16GB of RAM and 1GB of dedicated graphics, but there are two choices for processors and I don’t know which one to pick! Help! The base processor is 2.9GHz Core i5, and the upgraded version is 3.1 GHz Core i7 (extra $200). Which would you recommend? Thanks for your help!


I’d go with the i7 if only to build in a little overhead into your system, as well as future-proof it a bit.

The speed difference between the two isn’t significant enough to justify the price increase.

The bigger difference is that the i7 model has intel’s HyperThreading technology, which the i5 doesn’t have.

HyperThreading predates the modern multicore processors, and was originally created as a way of simulating a 2nd processor back in the day when all processors were only single core.

So it’s basically one physical processor acting as if it were two, on the occasions when it can, and the magic happens in a virtual environment.

A Multi-Core CPU does have physical cores built into it.

The i7 your looking at has 4 cores on it (also called a ‘quad’ core configuration). And with Hyper-Threading added into the mix, that becomes 8 virtual cores… which the OS will recognize and use when possible. BUT, the software has to be written so that it takes advantage of the additional cores as well, and that’s not always the case.

So having hyper-threading doesn’t always make a difference for a single program (if it’s not optimized for it). But if you ran multiple programs at once, it will be utilized collectively (if not individually), because the OS will spread the task load out across the virtual cores.

Lots of interesting articles on this stuff which explain it better than I do, here’s one of them…

Just so you know, SketchUp does not currently take advantage of multiple cores or hyper-threading. But who knows what future releases may do? Also, it is possible that rendering programs may make use of the CPU.

Thanks Y’all!! I really appreciate the great advice and feedback. Made our decision.