The third generation core i series (including the Pentiums) all use the LGA 1155 socket. Within this socket there are different chipsets, the most common three of which are z77, h77, and b75. The z77 is the most expensive and 'best' of the three, as it is the only chipset which allows overclocking (but only if you have an unlocked, "k" series chip) and usually has the most features.
There are two common kinds of graphics card connections - PCIe 3.0 and PCIe 2.0, however, they really don't matter. While PCIe 3.0 has almost double the data transfer bandwidth of 2.0, there isn't any card out there that will have a significant drawback on a 2.0 slot. PCIe 3.0 is currently only a valuable feature in multiple card setups, where each card is running with 8 lanes instead of the full 16, which means that the bandwidth advantage of 3.0 comes into play.
Now. As for motherboards, there are two different sections: budget (not good for overclocking, no support for multiple cards, and less quality construction), which ranges from $80-100 or so, and enthusiast, which ranges from $100-150. While there are many motherboards that are significantly more expensive, unless you intend to set overclocking records, or require a certain feature such as thunderbolt or quad sli/xfire support, these motherboards are not worth the money.
Finally, I have three things that EVERY NEW BUILDER SHOULD KNOW:
1) The rule of thumb for building a gaming computer is to spend twice on your GPU what you do on your CPU. That means if you buy a $220 i5-3570k, you'd probably want to be looking at a $400 GTX 670 or 7970 HD.
2) A gaming computer shouldn't waste money on buying an i7. The only difference between a core i7 and a core i5 is that the i7 has hyperthreading, a technology which works wonders for photoshop, video editing, or other such double-precision tasks as that, but which DOES NOT GIVE A BENEFIT for single-precision workloads such as gaming. (Which is why a $220 core i5-3570k will perform EXACTLY THE SAME as a $330 core i7-3770k while gaming, meaning you shouldn't waste your money on it unless you intend to be doing heavy image editing, video editing, or rendering... so much so that spending $100 to shave a minute off each render is worth it to you.)
3) There are two parts you should NEVER EVER cheap out on. The first is the power supply - if you buy a low end PSU, even though it might save you $40, it will die on you. Quickly. And when it does, there's a good chance that it will catch on fire, explode, or completely ruin other components, which will be much more expensive then spending the extra $40 to get a quality unit.
The power supply is the most important part of your computer
The other thing that I wouldn't go cheap on is the case. The reason for this is pretty simple - the case is going to be the longest lasting part in your computer. You can completely replace the guts three, four, five times, and your case will still work just as well as it always did. In addition, having a nice (~$100) case means that your computer will be quieter, cooler, and best of all, much MUCH easier to build.
Finally, I don't know your budget, but here's what you would want to be aiming for in the end in order to have a very good gaming computer:
PCPartPicker part list /
Price breakdown by merchant /
Benchmarks
CPU: Intel Core i5-3570K 3.4GHz Quad-Core Processor ($189.99 @ Microcenter)
CPU Cooler: Cooler Master Hyper 212 EVO 82.9 CFM Sleeve Bearing CPU Cooler ($29.98 @ Outlet PC)
Motherboard: ASRock Z77 Extreme4 ATX LGA1155 Motherboard ($134.98 @ Amazon)
Memory: Corsair Vengeance 8GB (2 x 4GB) DDR3-1600 Memory ($47.98 @ Amazon)
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive ($69.98 @ Outlet PC)
Storage: Samsung 840 Series 120GB 2.5" Solid State Disk ($92.99 @ Adorama)
Video Card: EVGA GeForce GTX 670 2GB Video Card ($377.28 @ TigerDirect)
Case: BitFenix Ghost (Black) ATX Mid Tower Case ($98.98 @ Outlet PC)
Power Supply: SeaSonic G 550W 80 PLUS Gold Certified ATX12V / EPS12V Power Supply ($89.99 @ Newegg)
Optical Drive: Samsung SH-224BB DVD/CD Writer ($17.98 @ Outlet PC)
Operating System: Microsoft Windows 7 Home Premium SP1 (OEM) (64-bit) ($89.98 @ Outlet PC)
Total: $1240.11
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-04-04 20:47 EDT-0400)
Facebook
Twitter
Instagram