Right now I have a i3-2100 with a 550ti and I am planning to upgrade the 550ti to a radeon 5970. I am quite sure the 5970 might bottle-neck when gaming, but will this also affect BTC mining?
Mining and gaming have very different requirements.
Gaming can have several bottlenecks that can limit performance, any one of which can limit your FPS. Some of these limitations do NOT transfer over to BTC mining. For example, PCIe bandwidth and memory bandwidth can have a very large affect on Gaming, but are almost irrelevant to BTC mining. Gaming requires a very well rounded system, but BTC mining is very specific in what it needs. Bitcoin mining requires high core count, and a high clock speed. This is part of the reason why a 5970 is better than a 550ti: 3200 cores vs 192 cores. You can mine with no problems on a 5970 thru a PCIe 1x extender @ 800 core and 300 memory. Gaming would be HORRIBLE in those conditions.
