Consoles are pretty weak. They have some of the weakest CPUs I've ever seen. They are 8 cores (several are reserved for the OS), but at 1.75Ghz (that's AMD Ghz too). They only have 5-5.5GB of useable RAM (the rest is reserved for the OS). Source
The PS4 GPU is basically a HD 7870. Source
That's around a R9 270 or GTX 760. Source
Pretty simple to build yourself a full size steam machine better than that for $500.
PCPartPicker part list / Price breakdown by merchant
| Type | Item | Price |
|---|---|---|
| CPU | Intel Core i3-4150 3.5GHz Dual-Core Processor | $104.69 @ SuperBiiz |
| Motherboard | MSI H81M-P33 Micro ATX LGA1150 Motherboard | $44.85 @ OutletPC |
| Memory | G.Skill Ares Series 8GB (2 x 4GB) DDR3-1600 Memory | $55.99 @ Newegg |
| Storage | Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive | $47.96 @ NCIX US |
| Video Card | Asus Radeon R9 270X 2GB DirectCU II Video Card | $168.99 @ Directron |
| Case | BitFenix Neos Black ATX Mid Tower Case | $33.99 @ NCIX US |
| Power Supply | Corsair Builder 430W 80+ Bronze Certified ATX Power Supply | $39.99 @ Amazon |
| Prices include shipping, taxes, rebates, and discounts | ||
| Total | $496.46 | |
| Generated by PCPartPicker 2015-03-07 10:39 EST-0500 |
I didn't even cheap out on the case/PSU.
The hard part is for manufacturers to get them as small as a console, and not charge absurd amounts for that feat. In theory they should be getting parts cheaper than I've listed thanks to the buying in bulk and direct from manufacturer method, but they still aren't buying in bulk to the same scale as console manufacturers.