SLI Performance drops off

[Infuria]

Hi,

I'm new to the SLI world, and was hoping for some help.

First off my system specs:

Intel i7-940
Intel DX58SO - Latest BIOS revision
EVGA 8800GT - Latest Nvidia driver
XFX 8800GT
8GB G.Skill DDR3

Both games [edit: both Cards] give good performance individually

After playing a game (L4D, WoW) i will get SUPER good performance and then after a minute, or two FPS drops to a slide show. SLI indicator bar is full. CPU Utilization is low.

Very confused about what is happening

Any input would be great!

[norfolk]

I don"t know what the deal is with SLI but I was getting the same thing and I had 560Ti"s,Now that I have moved to one 580 all my games are much smoother,L4D2,D3,Dead island,BF3,Just to name a few.Not sure if it"s drivers or the games not playing nice with the hardware setup.

[Infuria]

Core temps / clocks on both GPU's look good according to the EVGA Precision tool.