The questions about the current Intel processors is the easiest to answer, so I will start with that:
Intel is currently producing several ranges of CPUs. Those meant for the consumer market are called the i3, i5 and i7 range.
- The CPUs marketed as
i3 are entry-level CPUs.
They are cheap. Often lacking features. But sufficient for single tasks (such as browsing, office work, etc etc)
- The CPUs marketed with
i5 are midlevel CPUs.
They often have more features (such as hyper treading), but they are more expensive.
- The CPUs marketed with
i7 are aimed at professionals.
They get even more features such as hardware virtualisation (VT-d, etc.,) more cores, more L3 cache, and higher clock rates. Most people do not need these features. It does not make sense to pay for them if you do not use them, since a typical i7 is more expensive than an i3 or i5.
All generations of these have a three or four-digit number after them. E.g. the first i7 CPU was called the
When Intel came out with the next generation of (faster) CPU's they added a suffix.
E.g. the second generation of i7s starts with 2xxx. The third generation starts with 3xxx.
Sandy Bridge and
These are names for specific generations of Intel CPUs. There are three generations of Intel CPUs currently on the market (as of July 2012) with the "i3/i5/i7" branding:
Nehalem is the name for the design of a set of Intel processors released from November 2008 onward. Nehalem model numbers have three digits after the series number; e.g. "i7 920".
Sandy bridge is the name for the design of a set of Intel processors released from January 2011 onward. In product marketing literature, computer manufacturers call these "2nd Generation Core (i3,i5,i7) Processors". Sandy Bridge model numbers have four digits after the series number; e.g. "i7-2500K". The addition of a "K" indicates that the processor's clock multiplier is "unlocKed", making it suitable for overclocking.
Ivy bridge is also a name for specific design of Intel CPU's. Ivy Bridge is the latest generation of Intel CPUs to be released to the production as of July 2012. Compared to Sandy Bridge, they use less power for the same performance, and add features such as PCI-Express 3.0 and USB 3.0 natively into the CPU. Ivy Bridge processors also introduce much more powerful graphics cores based on the HD4000 integrated graphics design, compared to Sandy Bridge's HD3000.
The Ivy Bridge microarchitecture is fundamentally the same design as Sandy Bridge, but since the feature size is only 22 nanometers (nm) compared to Sandy Bridge's 32 nm, more transistors can be fit into the same space, allowing for higher performance and more complex 3D rendering using the on-chip integrated graphics.
some figures attached with processor like i5-2500k so what does 2500k means etc..
i5 means mid-level CPU
2xxx means second generation
An i5 25xx is a second generation, consumer CPU from Intel.
The last two numbers indicate specific information, such as speed and the number of cores.
All of this is easy to find with a bit of help from a search engine.
If you want to know more details, then it is best to read some tech sites such as
Tom's hardware, Anand Tech or Tweakers, because in dept answers would be quite to long to post here.