Intel SpeedStep - Computer runs better with it off. Why Enable it?

I want to explain a specific scenario before I get an answer to my question. I work for a firm that is a Win 7 laptop only firm. We have 1000+ users and we are all on Dell's. The workload for the majority of the staff is to have multiple Excel files open along with a few Word and PDF docs open. Internet usage is to download documents and upload documents which can be from one document at a time to sometimes over 500MB of zipped documents in one download or upload.

So, we have been noticing some poor performance on some laptops and no real rhyme or reason. Just certain people who complain more often than others but a few people had some legit performance issues... We originally thought it could be the power adapter since we were buying aftermarket adapters and they were causing issues but it wasn't.. Eventually, after much troubleshooting, we disabled Intel SpeedStep and all the performance problems went away! So we started trying it on a few other machines and performance shot up considerably.

Now our firm is interested in disabling SpeedStep on all machines but they want to know the implications of doing so. Will it kill battery life much quicker? Will the laptop run much hotter?  Or will the usage stated above really not have much of an affect on the battery or the heat? Will we see performance issues elsewhere? We are also now considering disabling C-State but wanted to get another opinion. What do you think?

Thanks!