If you're running a quad core, something is seriously wrong. Take a picture of the Task manager on both the process and performance tab. Also, i7s aren't actually 8 cores. 4 are virtual cores. However, it'd be a substantial upgrade over what you have, especially if it's one of brand new ones. The clock speed on some of the i7s are lower, but they're still better. L3 cache, etc. etc. GGL had a 2.66 GHz i7
Though we also had a 1gbps line, so we could play with the rates on garrysmod to make things smoother.