I want to build a $900 Gaming PC

A couple of questions:

What will your monitor resolution be? 1080p? higher?

What form factor are you looking at for your case and motherboard? You want a standard motherboard with a mid tower? or itx with a smaller case?

this is a good build it is 960 us dollar http://pcpartpicker.com/p/369Bj you can do any thing on this well and it will serve you great but other people are welcome to give me feed back

PCPartPicker part list / Price breakdown by merchant / Benchmarks

CPU: Intel Core i5-4440 3.1GHz Quad-Core Processor ($174.29 @ Amazon)
Motherboard: Gigabyte GA-H81M-HD3 Micro ATX LGA1150 Motherboard ($47.49 @ Newegg)
Memory: GeIL EVO POTENZA 8GB (2 x 4GB) DDR3-1600 Memory ($64.99 @ Newegg)
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive ($57.99 @ NCIX US)
Video Card: Gigabyte GeForce GTX 770 2GB Video Card ($329.99 @ NCIX US)
Case: Cooler Master N200 MicroATX Mid Tower Case ($44.99 @ Microcenter)
Power Supply: EVGA 500W 80+ Bronze Certified ATX Power Supply ($39.99 @ NCIX US)
Optical Drive: Samsung SH-224DB/BEBE DVD/CD Writer ($16.98 @ OutletPC)
Operating System: Microsoft Windows 7 Home Premium SP1 (OEM) (64-bit) ($84.99 @ NCIX US)
Monitor: Asus VX228H 60Hz 21.5" Monitor ($139.99 @ Amazon)
Total: $1001.69
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2014-03-08 04:25 EST-0500)
what about this build(it is a mini tower but strong)

The Core i7 CPU is great but if the only thing you're doing is gaming and stuff like web-browsing, light video-editing and small projects for school or something then an i5 will be perfectly fine and you'd be able to put the money saved to better use. If you wish to overclock then you could go with the i5-3570K, which is practically the best CPU for gaming on the market today for the money. While the Core i7 would be better, almost every game does not and likely will not utilise multithreading for the next few years, which is what the Core i7's are good at. The Core i7s also cost a significant amount more.

There is also not much reason to have 16GB of RAM as games don't even use 8GB yet - if gaming and stuff I mentioned above is what you're going to do then a pair of dual-channel 4x2GB (8GB) RAM would be great. After you do this and change the motherboard (ASRock Z77 Extreme4 is a great MOBO though you can save more with the ASRock Z77 Extreme4-m, which removes one PCI-E expansion slot and the amount of USB ports) then you should be close to the $900 mark, or closer anyway.

Definitely go for the 4770K at that price, it's worth the extra $30 to get the hyperthreading. Since the PS4 and XB1 have eight core CPUs, games that come out in the next 5 years will most likely be optimized to run on 8 cores so there's a good chance that having the hyperthreading (which shows up as having 8 cores in Windows) might be an advantage for gaming down the road. Having the hyperthreading can also help you if you run some apps or downloads in the background while playing, that way you won't lose much framerate if any.

For the motherboard I'd really go for the Extreme4 over the Extreme6 for you since the main thing the Extreme6 has is an extra ethernet port which is useless to you since you want to use Wi-Fi. They both have a 12 power phase design and all solid gold caps and very similar features and layout, so why not just save yourself a little money? Also if you want good sound for your PC for very cheap I recommend getting a Sound Blaster Audigy 2 ZS used off of eBay. You can get one for like $15-20 and it will give you some awesome sound. That thing is 24-bit, 192kHz/108dB, THX/Dolby/DTS Certified. Most of the entry level sounds cards of today are complete garbage and you'd have to shell out like 150 bucks to get something as good. The onboard sound on motherboards is mostly just a codec chip so not only does it sound like crap but it also needs to use some CPU power to produce the sound, which can cost you a few frames per second in games. If you want to do that keep in mind that you'll need to have a motherboard that still has regular PCI slots (the extreme4 and 6 both do, but some boards don't).

For your RAM, 8GB is more than enough especially if your not using an SSD. With an SSD I'd recommend 16GB just so you can turn off virtual memory in Windows as the constant writing it requires can damage SSDs over time. If you do go with 16GB, get 2x 8GB kit, not a 4x 4GB one. The less memory slots you use the better it is for system stability. Personally I only use 1.5V RAM because that's the recommended value set by intel for its CPUs and chipsets and according to them higher voltages can damage the CPU. I know a lot of people still use 1.65V RAM despite this but to me any gains aren't really worth the risk.

I think the GTX 760, especially a factory overclocked one like the ASUS, will be enough to start you out. You'll be able to get 60fps on high settings at 1080p with it on most games. Then maybe when the Maxwell cards come out you can sell your 760 on ebay or something and upgrade to like a GTX 870. I usually upgrade my GPU every 12-18 months and ebay the old one and only end up paying like $100-150 for the upgrade.

Whatever you do , don't skimp on the Power Supply. If you equate a PC to a human being, the power supply would be equivalent to the human heart that pumps the lifeblood (in this case electricity) throughout the whole system. You wouldn't want a cheap heart right? Cheap PSUs cause a lot of instability and crashes particularly when gaming. They will often fail and have a much higher chance of damaging components when failing. That Corsair 650W 80+ Gold Certified for $89 is an insane deal,and it's modular too which means less of a mess in your case. 650W will be plenty even if you overclock, And even when Maxwell cards come out they will probably require even less power due to their increased efficiency and rumored fabrication process downsize to 20nm. Whatever you get make sure it's at the very least 80+ Bronze certified and that it has a minimum of 30Amps on the 12V rail. I just looked at the Corsair one again on Newegg to see how many amps it had on the 12V rail (it has 54) and noticed that it was sold out which doesn't surprise me because that is an insane deal.

For your case if you wanna spend 100 bucks then let me recommend the CoolerMaster HAF 922. The HAF series (which stands for High Air Flow) is great because it mostly makes use of 200mm fans which can move tons of air at much slower speeds and are therefore much quieter. My gaming rig is in a HAF X 942 and I love that case, it keeps everything super cool and I can barely hear it. If you look at the reviews on newegg, all the HAF cases have a 5/5 egg average rating, that should say something. The HAF 922 has front and top 200mm fans and also has a spot for an additional one on the side panel you can add later if you want. Whatever case you end up getting, try to get one with a top exhaust fan; heat rises and the quickest way to get that hot air out of the case is through a top exhaust fan.

About overclocking to 4.4GHz: with a good air cooler like the Hyper 212 Evo and some Arctic Silver 5 thermal paste and a case with good airflow it should be possible, but it's still somewhat luck of the draw, each individual CPU is different and some overclock more than others even though they're supposed to be the same.

Sorry for writing a novel, I just wanna help you out as much as I can since it's your first build. Hope at least some of it was helpful to you. Best of luck to you on your build, let me know how it turns out.

You have to go with a Z77 motherboard for the 3570K, the Z87 uses a different socket and is incompatible.

I have always been able to overclock without using water cooling. The Hyper 212 Evo and arctic silver 5 got my 2600K to 4.6GHz and it never goes above 63C under full load. A lot of the new motherboards have an easy overclock function in the BIOS where you just enable it and the motherboard gives you a good automatic overclock.