Macbook Pro i7 - But Not Quad Core?
 

I'm deciding between which used MBP to buy, and yesterday, it was brought to my attention that older i7 MBP's may not actually be quad core.

If you look on the official Apple Specs page (How to identify MacBook Pro models), Only the Early 2011 and newer MBP's have "Quad Core i7" processors, and the rest are just "i7". I also checked a benchmarking site (Mac Benchmarks - Geekbench Browser) which confirms this, and the pre-2011 MBP's with faster clock speed i7s are showing significantly lower benchmarks than the 2011-on MBPs. However, when I google the model of the processor, on sites like NewEgg, it states quad core, so I'm hearing both sides.

What is actually the case here?

Not all i7 chips are quad core, particularly the i7 mobile chips.

You will need to supply an example of newegg indicating a dual core chip as being quad core. If you are googling a specific mobile chip and not including the "M" on the end of the model #, then you are looking at the desktop version of the chip.
For the best results for identifying any particular Intel chip when using google related to a chip model # - would suggest you limit your clicking to the Intel product page which would be ark.Intel.com/products/xxxxx.

As initially introduced by Intel, no i7 mobile chip was quad core. Don't really understand why they called them an i7 since most people expected "all" i7s to be quad core. The i7-M in any '10 model MBP is going to be a 2 core chip capable of 4 threads.

Try using everymac.com for more specifics all around about any Mac you're looking at.

I was under the same impression with the name change to i3, i5 and i7. I initially thought that i3 just meant a dual-core CPU, i5 was a quad-core and i7 was a quad-core with virtualization yielding 4 additional cores. However, as Bobtomay said, just the i* name doesn't indicate the number of cores, but the family indicates whether it has 2 or 4 cores..

Like you mentioned...some of the early i7 MacBook Pro's had 2 cores. Early 2011 i7 MacBook Pro's (and newer) have 4 cores.

I'm pretty sure all 13" MacBook Pro's with an i7 only have two cores (even the latest models).

Of course once you have specific model/models you are interested in buying...it's always a great idea to verify its specs before buying.

- Nick