Medium settings for Crysis are hard to get on a budget. BF 4 isn't as bad, but that rig won't run it at medium. The cheapest thing you could get for that would be around $400 to $500. I have never played Crysis, but I do know it is one of the most demanding games out there to date. For a good mainstream rig I'd recommend something like this:
[PCPartPicker part list](http://pcpartpicker.com/p/cRD7bv) / [Price breakdown by merchant](http://pcpartpicker.com/p/cRD7bv/by_merchant/)
Type|Item|Price
:----|:----|:----
**CPU** | [AMD FX-6300 3.5GHz 6-Core Processor](http://pcpartpicker.com/part/amd-cpu-fd6300wmhkbox) | $96.99 @ SuperBiiz
**Motherboard** | [MSI 970A-G43 ATX AM3+ Motherboard](http://pcpartpicker.com/part/msi-motherboard-970ag43) | $59.99 @ SuperBiiz
**Memory** | [G.Skill AEGIS 8GB (2 x 4GB) DDR3-1600 Memory](http://pcpartpicker.com/part/gskill-memory-f31600c11d8gis) | $43.99 @ Newegg
**Storage** | [Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive](http://pcpartpicker.com/part/western-digital-internal-hard-drive-wd10ezex) | $52.49 @ OutletPC
**Video Card** | [Gigabyte Radeon R9 285 2GB WINDFORCE 2X Video Card](http://pcpartpicker.com/part/gigabyte-video-card-gvr9285wf2oc2gd) | $172.98 @ Newegg
**Case** | [Corsair 100R ATX Mid Tower Case](http://pcpartpicker.com/part/corsair-case-cc9011075ww) | $39.99 @ Micro Center
**Power Supply** | [Corsair Builder 500W 80+ Bronze Certified ATX Power Supply](http://pcpartpicker.com/part/corsair-power-supply-cx500) | $25.00 @ Newegg
**Optical Drive** | [Asus DRW-24B1ST/BLK/B/AS DVD/CD Writer](http://pcpartpicker.com/part/asus-optical-drive-drw24b1stblkbas) | $18.75 @ OutletPC
| *Prices include shipping, taxes, rebates, and discounts* |
| Total (before mail-in rebates) | $575.18
| Mail-in rebates | -$65.00
| **Total** | **$510.18**
| Generated by [PCPartPicker](http://pcpartpicker.com) 2015-07-23 23:31 EDT-0400 |
A lower end GPU like an R9 270 could be used instead of the 285, but it wouldn't be that much cheaper and would be noticably slower. I wouldn't recommend anything lower than an R9 270. The 285 will run most anything on high to max settings with good frame rates. Remember, when building a rig you can buy certain parts and not worry about them being dead and needing to be returned so you can space the purchases out a bit. The CPU and case can be bought first as they don't need to be tested for failure. The board, GPU, RAM, power supply, and hard drives should be bought at around the same time in case they arrive dead. That way you stay within the 30 days the retailer gives you to return faulty hardware.