Need advice for a possible PC upgrade

[Arkeolog4]

So, a week ago I experienced an error <orange/black lines on screen> with my GPU(an HD 4890), and ever since then whenever the GPU clock exceeds a certain limit (something around 550 MHz ) I get a black screen, my display driver crashes and cannot recover. I found a temporary solution to my problem by setting the max clock 490 MHz on AMD Overdrive, but I assume that I will need to replace it soon enough.
Let me list my specs first:
-Gigabyte EP41-UD3L Motherboard
-Intel Core 2 Quad Q8200 2.33 GHz CPU
-HIS ATI Radeon HD 4890 1GB GPU
-Antec EA-650 650W PSU
-2x2 GB Kingston DDR2 RAM
I was thinking of getting an R9 270 to replace it, but I guess that I will need to replace my CPU to prevent bottlenecking and maybe add a little more RAM. So I want to ask advice as to what CPU I should procure (not exceeding 150$) or am waiting for someone to tell me my efforts are meaningless for my aging 4.5 year old PC. Or it might even be that the error I received isn't hardware related at all (even though I formatted my PC)... So thanks in advance for helping this very low-range enthusiast!

 

[Oleonius]

I think these are the right components to upgrade.

- For the card, I suggest picking the R9 270X instead of the R9 270. With the Mantle API coming soon, this card will perform great.

- For the CPU, it's up to you. If you want to stick to AMD, the FX-8320 or FX-8350 CPU will be fine for gaming.

- For RAM, get a 8 GB kit. It will be plenty of memory to run all games.

[PCPartPicker part list](http://pcpartpicker.com/p/2JzTy) / [Price breakdown by merchant](http://pcpartpicker.com/p/2JzTy/by_merchant/) / [Benchmarks](http://pcpartpicker.com/p/2JzTy/benchmarks/)

Type|Item|Price
:----|:----|:----
**CPU** | [AMD FX-8350 4.0GHz 8-Core Processor](http://pcpartpicker.com/part/amd-cpu-fd8350frhkbox) | $194.98 @ OutletPC
**Motherboard** | [Gigabyte GA-990FXA-UD3 ATX AM3+ Motherboard](http://pcpartpicker.com/part/gigabyte-motherboard-ga990fxaud3) | $124.99 @ Microcenter
**Memory** | [Kingston Black Series 8GB (2 x 4GB) DDR3-1600 Memory](http://pcpartpicker.com/part/kingston-memory-khx16c9b1bk28) | $79.99 @ Amazon
**Video Card** | [HIS Radeon R9 270X 2GB Video Card](http://pcpartpicker.com/part/his-video-card-h270xqm2g2m) | $262.67 @ Amazon
| | **Total**
| Prices include shipping, taxes, and discounts when available. | $662.63
| Generated by PCPartPicker 2014-01-29 07:30 EST-0500 |