Since i already had a laptop, gpu and a case, all that was left to buy was the power supply (£23 second hand) and expresscard pci to pcie x16 slot adapter (£35)
Specs:
Lenovo T430
CPU: Intel i5-3320M (ivy bridge)
GPU: HD4000 (iGPU) + ASUS Matrix HD7970 (GDC Beast v8 [8.4D] eGPU)
RAM: 8GB 1600MHZ DDR3 (2X4GB Dual channel)
Display: 1600X900 @60HZ (internal, iGPU) + 1680X1050 @120HZ (external, eGPU)
eGPU PSU: Corsair CX430
SSD: Samsung 850 EVO 500GB
Although the expresscard slot only allowed me to run the card at PCIE 2.0 X1 i actually found the performance to be quite decent and I'm surprised how well it works.
With integrated graphics I would get 28-40FPS in project cars on lowest settings and 720p which dropped to 18-25fps after some time.
Now with eGPU with all the settings maxed out/ultra (apart from grass due to CPU bottleneck ), no AA (I find FXAA to be good enough) and native resolution I get 50+ FPS (usually above 60fps with occasional drops).
I might upgrade to 4C/8T i7 from 2c/4t i5 but i don't have money for that right now (they still go for over £100).
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