Okay, so I found this,
This is exactly how bitcoinwatch estimates FLOPS. I am not saying it is an acurate way to do the estimate, all I am saying is this is how they do it for what it is worth and for comparison to your other methods. Many here among us question the valididty of this estimation method.
The page simply uses the following assumptions/estimates:
1 INTOP = 2 FLOP
1 hash = 6.35K INTOP
1 hash = 12.7K FLOP
So the hashrate in TeraFLOP/s is simply 12.7 times the hashrate in Gigahashes/s.
As an example: 11,558.55 Gigahashs/s * 12.7 TeraFLOP/Gigahash = 146,794 TeraFLOP/s = 146 PetaFLOP/s
Is this accurate? What 'disclaimers' would need to be in front of this if used as a reference?
That is a good rule of thumb but there is no exact metric like 12 inches = 1 foot. The exact ratio between integer performance and floating point performance depends on the chip architecture, other hardware factor, and operating system.