iMac Core i5s - any difference?

[VaatiKaiba]

I've been browsing the Apple Store pricing up some iMacs, and I've just noticed that the first 27" model allows you to upgrade to a 3.6GHz i5 processor (from the i3), and with the same graphics card as the highest end iMac, is only about €14 more expensive. But when I look at it in my basket, it comes up like this:

I just want to check - is the 3.6GHz one quad-core even though it doesn't specifically say it? I thought that all iX processors were quad-core...

Thanks in advance!

 

[Hellhammer]

3.6GHz i5 = Dual core with Hyper-Threading (4 threads)
2.8GHz i5 = Quad core without HT

Only some i5s and i7s (desktop) are quad core. More specifically, all i3s are dual core and i5-6xx are duals too. i5-7xx and all i7s (excluding 970, 980X and 990X which are 6-core) are quad core. They score about the same in GeekBench. More benchmarks here!

The quad core is still faster as you can see in the benchmarks, thus I would get it

 

[VaatiKaiba]

3.6GHz i5 = Dual core with Hyper-Threading (4 threads)
2.8GHz i5 = Quad core without HT

Only some i5s and i7s (desktop) are quad core. More specifically, all i3s are dual core and i5-6xx are duals too. i5-7xx and all i7s (excluding 970, 980X and 990X which are 6-core) are quad core. They score about the same in GeekBench. More benchmarks here!

The quad core is still faster as you can see in the benchmarks, thus I would get it

Wow, ok so I was completely wrong - thanks very much for your help!

 

[zhenya]

With the faster clock speed, the dual core processor should be faster in situations where cpu horsepower is the primary consideration - especially when using programs that are not optimized to utilize multiple cores. The quad core will be faster when performing many tasks simultaneously. Because the dual-core has hyperthreading, it will appear to the OS as 4 cores.

Looking at those benchmark pages you can see just that - in some tests the 3.6 is faster, in others it's the 2.8 quad. Overall scores seem to lean slightly in favor of the 3.6 (from those two pages, if I'm reading it correctly), but the two should be so close overall as to not matter to most people.