So, back in late 2009 I built this system
Specs:
Gigabyte X58-UD3R Motherboard
Core i7 920 @3.8ghz with Thermalright air cooler
Corsair 850 PSU
12GB 1600mhz DDR3 (4x3)
XFX Radeon HD 5870 (max overclock) with a custom Thermalright cooler
The system has performed flawlessly and been a beast. But now in 2015 it was starting show its age (still playing games well), but i wanted more. But, my budget currently didn't give me the budget to build new. So, instead I spent a total of $191 and picked up a 6core/12thread overclockable Xeon x5650 cpu for $56 and also a MSI R9 280x for $135 (said to be 4 months old). This seems to have been a great bang-for-the-buck upgrade. Yes, I know many of you will say the CPU upgrade was worthless, but for $56 I felt it was worth the shot. The TDP of the Xeon makes my system run even cooler, and performs better even in single core benchmarks. Also, if DirectX 12 works the way they are saying and lets API's use all threads, I'll have an additional 4 threads with the xeon, and give me even a better overall upgrade for minimal $$.
Here are the results (not extensive tweaking or testing yet)
Core i7 920 @3.8ghz, air cooled, idle temps 35c, 100% load temps 70c
Radeon 5870 core clock 900, mem clock 1300
Xeon x5650 @4.4ghz, air cooled, idle temps 26c, 100% load temps 58c
MSI R9 280x core clock 1150, mem clock 1650
Benchmarks:
Intel ETU CPU Benchmark
i7 920 - 442
x5650 - 592
Cinebench Benchmark
CPU
i7 920 - 602
x5650 - 1026
CPU Single core
i7 920 - 118
x5650 - 137
Open GL
i7 920 - 96.22
x5650 - 114.79
Firestrike
5870 - 2995
280x - 8482
Valley (ultra 1080p)
5870 - 40.7fps / 1701
280x - 77.9fps / 3148
I'm pleased with my results so far and also how cool the system runs. I think for the little amount of money I put into this 5 year old system, I've made it usable for a good bit longer. And as I said before, with the way dx12 is supposed to use all threads for game api's, it'll even be a better upgrade overall.