I'd say that these days it is too fast - people, including researchers - reflect too little before something is written down, submitted, or even constructed, because these ideas are not analyzed well enough. Research has become shallow, debates have become shallow, thoughts in general are too narrow-minded. If you wish to reflect more on this, I recommend a VERY clarifying book to read: "Amusing Ourselves to Death" by Neil Postman. Revealing indeed.

I assume that both the question and the expected responses in this context are not rhetorical and some scientific facts are indeed expected.

Philosophically, speed of thought could be faster than light since we can just think of sun and then back on earth again within a fraction of second which is much less than the actual travel time of 8 minutes by light. But in that context, "sun" is just a collection of discrete data inside one small compartment of our cortex and we just visited that without actually traveling the distance physically.

For that matter, speed of thought scientifically is measured as the response time of nerves when an external stimulation is applied. In a simple situation as such for a sprinter, this response/reaction time is ~ 150 ms. But when the complexity of the problem is increased such as answering a difficult question in interview, or figuring out path in a forest/desert, or solving a complex equation, human response time could be in seconds, minutes, hours......

So, speed of thought is problem specific and also situation specific. If outside environmental conditions are changed (increase/decrease in temperature, pressure), that would have a serious impact on the thought process and even a performing simple problem might seem impossible (asking a person doing 2+2 in hypothermic situation).

In finer aspect, it also would depend on the neuron characteristics in the nervous system. For example,myelinated neurons that connect spinal cord and muscle, can carry signal at 70 - 120 m/s, but unmyelinated neurons carry signals only at 0.5 - 2.0 m/s.

Have a look at the below article for a lucid discussion on the topic:

http://theconversation.com/it-feels-instantaneous-but-how-long-does-it-really-take-to-think-a-thought-42392

However, if a more quantified discussion on the topic is desired, these old references wouldn't be too obsolete:

http://bitsavers.informatik.uni-stuttgart.de/pdf/rand/ipl/P-1734_The_Simulation_Of_Human_Thought_Jun59.pdf

http://cvcl.mit.edu/SUNSeminar/sternberg_memory_s66.pdf

Thanks Michael. Subhashish, thanks for the valuable inputs, u got my question precisely. Satisfied.