I5 660 or i5 750??

750 is a quad, not a dual.

but in answer to the question, the 750 is vastly superior. if you can afford it, buy it. IMO

+1^
750 is a quad core and has 4 cores with 8 threads whereas the 660 has 2 cores with 4 threads,both are good but 750 is a better choice

+2^

750 is a much better choice as it has 4 Real cores.It is an i7 level performer.

+3^

750 is a true quad core, but only utilises 4 threads unlike what Maziar says (sorry dude!)
660 is a dual core but hyperthreads for 4 logical cores.

i5-750 lacks hyperthreading... that's what differentiates it from the i7-860 and i7-870... that and a little bit of clock speed. Still... 4 cores > 2 cores + hyperthreading.

I'm wondering about this too. I guess it depends upon what exactly you want to do with it.

Some things the 660 has that the 750 does not:

The 660 contains built in graphics.
It contains some virtualization features. http://download.intel.com/technology/computing/vptech/Intel(r)_VT_for_Direct_IO.pdf

It contains some hardware based execution isolation features. I don't know if windows 7 supports this or not.
It supports hardware based encryption instructions. If you keep your hard drive encrypted, this could be useful.

The 660 is 32nm vs 45 nm. I don't know what that really gets you. More speed with less energy?
The 660 uses 73w vs 95w.
The 750 contains twice as many transisters as the 660.

I think the 660 is geared more towards business.

does both (660 and 750) support vPro?

32nm is the better option here. nm stands for nanometers, as-in the measurement of the microchip in the processor. The smaller the chip, the lower the temperature and power usage.



again, this is another scenario where you want the lowest possible number. Thus the 660's 73w power usage is preferable.



This is true, although, while the 750 contains twice the number of transistors, the 660 has an integrated graphics module, with a base frequency of 733 MHz(comparable to Nvidia's GeForce 9800GTX).

You will also find that the 660 utilizes Intel's Trusted Execution Technology, which basically acts as a means to prevent malicious software attacks. You can consider it a hard-firewall built into the CPU.

While the 660 is dual core, it has hyper-threading allowing it to process 4 threads simultaneously, while still maintaining the highest frequency for applications and games that only support dual core processing.

The 750 has a larger cache... however, the 660's integrated graphics module, the high frequency and hyper-threading, the low power consumption, and the smaller architecture (lower temps) make the 660 the preferable CPU for your average computer user, and even casual gamers who run single video card systems.

I would only suggest the 750 over the 660 to a person who has or intends to have an SLI set up.

Addendum; Get the 660!.. unless you have 2 or more graphics cards..



**EDIT**
Source:
http://ark.intel.com/Product.aspx?id=42915
http://ark.intel.com/Product.aspx?id=43550