Depending on your motherboard, that socket does support up to a 6 core i7 975X CPU, which are still okay-ish. Particularly at productivity tasks which can use all 6 cores/12 threads that CPU has to offer, they're not too far behind modern Intel quad cores.
However for gaming the 6 cores doesn't really give you much.
Those old i7 920s are pretty beastly overclockers though. Most can get close to 4Ghz with a decent cooling and patient tweaking, particularly if you have RAM which can run stably at 1600Mhz (that allows you to set a 200Mhz BLCK with a 8x RAM multiplier - and then OCing is pretty straightforward from there).
If you're still running the stock cooler, maybe a better cooler is the right investment? Check the specs, but most decent coolers will come with multiple mounting kits allowing you to re-use it if/when you decide to upgrade the entire build in future. So it's a reasonable long-term investment too, particularly if you can get ~%50 better CPU performance out of a 3.8-4Ghz OC.