How to record gameplay without a dip in framerate

So, this tutorial has a review of recording devices, including ones that support HD recording. It does note the following

I WILL BE LISTING SOME HD COMPATIBLE RECORDING DEVICES that enable you to record in standard and play in High Def simultaneously later in this article. However the prices can vary dramatically on these devices. There is only one somewhat affordable external device that allows true HD capture and that is the Hauppauge HD PVR and it is listed below.

It also says

As far as I know there are no affordable external devices that record 1080p or from an HDMI cable. The Hauppauge will do HD but it will only record in 720p or 1080i.

Mind you, this guide was posted 3 years ago so there is no guarantee that the devices haven't improved since then, but this seems to be a very complete guide.

Honestly, I think you're going to find better support on the GameDev side of things. A lot of players record their videos (especially those in MLG) but a lot of the times they won't care about audio syncing, or perfect framerates. You can take a look at this guide over at the MLG forums, but a lot of their focus is on cheap rather than quality.

Well turns out I discovered the answer to this myself.

Fraps heavily writes to the HDD, and slows down the game if it can't write the videos fast enough. For me, this was because my HDD was becoming rapidly fragmented as Fraps ran over long periods of time (about 10% after 1 hour). This was causing Fraps to not be able to keep up with the action.

From my research, there are two fixes to this:

• Record to a second HDD dedicated to Fraps
• Set Fraps to record at a lower resolution or lower framerate. For instance, record at 30fps, but turn off framerate lock so the game isn't reduced to 30fps (probably the best solution).
• Take a break every time Fraps decides to slow down, and defrag your disk.

I hope this helps someone out in the future!