ThinkPad X220 Tablet + EXP GDC Beast 8.5c + Gigabyte GTX 660 Ti (working and stable at Gen 2)
Having benefited greatly from following the advice of other posters on this forum, I think it's only right to share my experiences on breathing a new lease of life -- certainly from a gaming perspective -- into my trusty ThinkPad.
So: I paired an EXP GDC Beast (8.5c) with my ThinkPad X220 Tablet (i7 2640M, 8GB RAM, 250GB SSD). I used the Beast with an Expresscard-type connector and a Gigabyte GTX 660 Ti GPU. At first I experienced nothing but crashes and rising levels of frustration in yours truly. Wrapping all the leads in silver foil (then earthing them) and fitting ferrite sleeves didn't stop the system crashing once it had been under load (i.e. gaming) for anything from a few seconds to around 30 mins. The remedy to my headache came when I swapped-out my [frankly - and with the benefit of hindsight - 'crap'] Chinese 'CIT'-branded 500W PSU for a fully modular 750W Seasonic Focus Gold unit (overkill, I know, but I can use this PSU in a forthcoming desktop build). I do use the laptop's screen and realise that this delivers around a 20% performance hit -- but hey, even this less-than-perfect setup offers markedly better real-life performance than my machine's integrated HD3000 GPU delivered:
In Unigene's Heaven Benchmark 4.0, I achieved 63.6 FPS and a score of 1603 (@1366*768 resolution) with all the settings maxed (including tessellation); the same benchmark in low quality delivered 82.8 FPS and a score of 2087. In ME3 MP, I get 45-50 FPS, and in Crysis 2, 60+ FPS at high settings (which surprises somewhat me as I thought Crysis 2 was the more graphically-demanding game). I am using the latest Nvidia driver (417.01), which works fine.
GPU-Z informs me that my bus speed is PCIe * 16 2.0 @ * 1 2.0, and I've encountered no problems with stability there.
In conclusion, I'd say that for an outlay of around £120 (excluding shipping: £45 for the brand-new Seasonic PSU (got a result on eBay there)), £30 for the GDC Beast and £45 for the GTX 660 Ti), this upgrade was certainly worth doing.
@nick_vasey, did you want to complete a build template so your system can be listed as a eGPU.io's Build Guide?
For the sake of completeness, today I plugged my EXP GDC Beast's GTX 660 Ti into an external monitor via HDMI-HDMI. Odd thing is that whilst in-game FPS rates have increased significantly (from the mid 40s to 60+, even though the required resolution has been upped from the laptop's 1366*768 to the external monitor's 1920*1080), my score in Heaven Benchmark 4.0 seems to have dropped by a similar percentage. I'll do more tests -- for science's sake 🙂 -- and, should I discover anything of note, report back.