I currently have the Lenovo y50 (4710hq, 8gb ram, 860m) and am looking to either add an external GPU or build a new PC. Will the performance impact from using PCIe 1x be significant enough with a high-end GPU (1080/1070) to justify building a new PC? I don't care about portability or having the cover off and already using an external monitor. Would this be a good temporary solution as I will probably end up building a PC once I save up a little more?