[conservatism_IS_compassion]

Core2 duo, as I recall . . . I upgraded the RAM to the max of 4G a good while ago.

[__rvx86]

Unless the hardware (motherboard) or firmware specifically restricts it, there should not be any reason as to why your iMac could not address more memory. The Intel Core 2, like all the other processors used in Intel-based Macs, supports the AMD64 extensions.

I think yours goes up to 64GB of total memory...also, since we're already at that point, I think you should check your security settings, as described in the article.

The 4GB limit is a relic of the original i386 micro-architecture; even modern 32-bit processors (since the Pentium Pro) could address more than 4GB of RAM using something called Physical Address Extension, to 36 bits.

[__rvx86]

Whoops, I think the actual limit, for your particular iMac, is actually 32GB....if you look up your exact iMac model online, it should tell you—but it is definitely more than 4GB...