Strange FPS issues

[Nixman]

After reporting an issue with Enders client where by porting to Boston or switching characters would result in severe stuttering every 2 seconds, I started testing a few things to ensure my computer wasn't at fault, while the Ender issues is persisting I have also come across a strange FPS issue with all clients including vanilla.

Using fraps, on the log in screen of the vanilla (and Enders) my FPS will basically sit at 32FPS, however, if I open google or any other window and move my mouse, or use the keyboard my FPS will shoot up to 50. If I stop moving the mouse or typing, it will go back down to 32. Even with the flashing input cursor you get when typing i can watch the FPS go up and down in tandem.

All my drivers are up-to-date etc, have plenty of RAM and all that and used to play quite happily on 50FPS, this has only seemed to happen recently with no changes to my computer.

Anyone have any ideas?

[HasseKebab]

watch the FPS go up and down in tandem.

All my drivers are up-to-date etc, have plenty of RAM and all that and used to play quite happily on 50FPS, this has only seemed to happen recently with no changes to my computer.

How much RAM?

[Nixman]

4 Gig

[HasseKebab]

4 Gig

should be enough, what java version are you using?
are you having any other programs up?

[Nixman]

only Vanilla Salem, Fraps and Google Chrome

Using Java 7 version 9 (latest)