I was wondering if using a SSD would reduce lag and stuttering .Some say yes some say no .Perhaps you can enlighten me .Share some info and stuff .Im asking because sometimes FNV and FO 3 lags and and kinda freezes for a second when i shoot then it goes back to normal .
Or maybe is the sound card ?Or something else ?

No, a SSD would not have a noticeable effect on your gaming performance. The biggest advantages of a SSD are how quickly it can load data - the OS benefitting most from this - and their improved durability (non-volatile flash memory vs. a mechanical disc with physical parts)

Here's a look at some fairly extensive testing that was done to answer this exact question.

http://www.hardocp.com/article/2013/12/10/hdd_vs_ssd_real_world_gaming_performance/1#.ViTdKit3Z_E

As you can see, testing the same PC with a standard HDD vs. a SSD had absolutely no relevance on the performance of the games tested and in one case, the standard drive had higher minimum FPS than the SSD.

If you're having FPS issues, your GPU and RAM are what you need to look at upgrading, or possibly your CPU/Motherboard if your PC is more than a few years old.

Defragging your system from time to time can help with performance as well, If you have a Nvidia card you could use the Gaming Experience app your card comes with and set it to overclock for maximum performance as well. Unparking your CPU's cores can also help, or at least for Skyrim.

All righ,thx 4 the info .I thought buying a SSD will solve the problem .But i guess its just Fallout being what Fallout does best .Also i do defragment my disc every month .