>>266367679
The Rift S or even one of the gen1 headsets are the better choices if you have low end hardware since you won't be trying to hit the higher resolution or framerate of the Index. Still at those specs it's going to be tough and many games won't run well.

I used an overclocked i5 2500k and a GTX 970 on a Rift S. Real world performance probably not too dissimilar from your specs if userbenchmark is anything to go by. The experience varied from okay to unplayable and almost all of the ones that were playable had to be on the lowest settings. Pavlov was playable up to a certain number of players but it also varied by map. VRChat just feels awful being so CPu heavy. H3VR was not a smooth experience in take and hold. Job sim type games worked but I couldn't do anything about the jaggies everywhere. Something like No Man's Sky will rape your eyes and probably crash if you're not careful.

For the price of an Index you're just better off getting something else and spending the rest upgrading your specs. A decent framerate and the possibility to supersample or actually play optimized games will beat the novelty of owning the best VR set but not being able to properly enjoy it.