I thought all the i5s were quad-core ........ ah, I see the 2390T is dual core.2.4GHz Intel Core 2 Duo
VS.
2.3GHz dual-core Intel i5
Price difference between the two computers is 80 dollars.
All other components are comparable and the same.
I don't think that's necessarily the case. The motherboard in my studio PC will be turning 5 in July, along with the Core 2 Duo E6600 CPU that I bought for it. When it was purchased it was in the top of its product line, and it performs at the same level as my 2011 MacBook Pro. Sure the architecture behind the i5 series is different than the Core 2, but why upgrade just because it's a new product? Technology is lasting so much longer than it did even 5 or 6 years ago. BTW I'm assuming you're looking on EBay for a Core 2 Duo.The Core i5 uses a newer architecture, so it will be a lot faster, as well as more suitable for future upgrades. The LGA 775 socket is obsolete now, so buying a Core 2 Duo doesn't make much sense.
Just make sure your motherboard is compatible with the CPU.
I don't think that's necessarily the case. The motherboard in my studio PC will be turning 5 in July, along with the Core 2 Duo E6600 CPU that I bought for it. When it was purchased it was in the top of its product line, and it performs at the same level as my 2011 MacBook Pro. Sure the architecture behind the i5 series is different than the Core 2, but why upgrade just because it's a new product? Technology is lasting so much longer than it did even 5 or 6 years ago. BTW I'm assuming you're looking on EBay for a Core 2 Duo.
A good amount of the performance of a CPU also has to do with the bus speeds of the motherboard. Do you have the make/model of the board that you have?