Not sure if you need a monitor so I just included in the build:
PCPartPicker part list / Price breakdown by merchant
| Type | Item | Price |
|---|---|---|
| CPU | Intel Core i5-4690K 3.5GHz Quad-Core Processor | $259.98 |
| Motherboard | ASRock Z97 Anniversary ATX LGA1150 Motherboard | $0.00 |
| Memory | Corsair Vengeance 8GB (2 x 4GB) DDR3-1600 Memory | $48.99 @ Newegg |
| Storage | Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive | $49.99 @ Newegg |
| Video Card | HIS Radeon HD 7950 3GB Video Card | $129.00 |
| Case | Thermaltake Versa H21 ATX Mid Tower Case | $32.99 @ SuperBiiz |
Power Supply | EVGA 500W 80+ Bronze Certified ATX Power Supply | $42.99 @ SuperBiiz Monitor | Acer S220HQLAbd 60Hz 21.5" Monitor | $99.98 @ B&H | Prices include shipping, taxes, rebates, and discounts | | Total | $663.92 | Generated by PCPartPicker 2015-06-16 06:34 EDT-0400 |
You should also by the Hyper 212 Evo but strangely enough PCPartpicker isn't displaying it. You should overclock as it will make a difference for CAD programs.
Other things you can upgrade:
Get another 8GB of RAM
Unfortunately, you cannot get a smaller case and maintain performance without raising up the price. Get the GPU here: http://gpushack.com/collections/all-gpus-for-sale/products/his-iceq-hd-7950-boost with code HIS20