I am running a windows 8.1 quad core, with word 2007, 8 gigs of ram, and yes I do agree that NVDA behaves slowly with microsoft word documents in general, no matter the size. Even a blank one it will still take a second before it says blank when I hit an arrow key.

I've only seen either one of these issues pop up once, on a Dell Latitude laptop.  reproducing them is finicky, since there doesn't seem to be any particular set magic formula or logic behind them; perhaps the drive on the machine I'm thinking of is just shot.  Otherwise, I haven't seen anything of the sort whatsoever.

It got fixed in a windows update, the NV access guys did say the lag in file explorer was a MS thing, and nothing they could fix, then, after one update, it wen away. There's still just a touch of lag in there from time to time, but its not like it was. When I used Word, I did notice a lag in it .But, I use Libre Office now.

Thank you all for your answers.
Avoiding windows explorer and word would avoid more than 70% of my work on my PC.
I personally believe this is due to my tiny processor 1.4 GHZ, since on my desktop that is built in a 3.0 GHZ processor this lag never occurs.
When I set my laptop to high performance, thigs get better a bit.
Jaws, on the other hand, doesn't face this issue, and that is very sad that NVDA should because it runs flawlessly in other areas of windows.

Thanks for your suggestion, but I am back to jaws. I can't make the big change to switch to NVDA. it's really hard for me. Although I customised NVDA in exactly the way jaws works with commands, but still I find jaws faster, especially in three areas, windows explorer, microsoft office products and internet explorer/mozilla firefox. I am currently studying at university, so I have to deal everyday with large books which sometimes go up to 400 pages. Jaws handals faster these documents plus provides major support for microsoft word and excel. I spent a whole week working with NVDA and things were getting harder for me, so I was kindly forced to go back to jaws. It got me very annoyed when working with tables because it took around three seconds to read the items on them. I am using an updated version of jaws 16 which works nicely and does the job well enough on microsoft word.
If NVDA solved these issues I have, it would be very likely for me to completely switch to it. But till then, I will continue to keep a very keen eye on NVDA updates and see what happens.
It's the best screen reader second to jaws though.

good luck on mak!

Bryant, that's not the only problem, the issue you are talking about may be somewhat fixed if you realise that a certain program just crashed and press windows+m to go to the desktop. It is actually facing other problems. It should be faster on internet explorer and mozilla firefox. The only place on internet where NVDA satisfies me is google chrome, that if it were more accessible, hard it would be not to switch to it. They should also implement some new commands on microsoft word and other office products. Also, something I think they should do is an integration of their synthesisers or better say speech dictionaries because users are forced to place in the dictionary words that are very basic. Nowadays, the problem does not fall on the size of the screen reader setup, I personally would accept NVDA or whatever screen reader even if it required 50 GB on my harddisk provided that it met my needs.
Today, I'm not complaining about countless numbers of add-ons that should be installed on my NVDA copy, it is very simple for me as I downloaded most of them on my PC and installing them it's not a big deal, after all, they will be always there even if you update NVDA. you can even make a portable copy of it, copy to a USB and install it on another computer, with the same configurations. I can even help a new user of NVDA by customising it in the way jaws works, including commands, web navigation, symbol pronunciation and dictionary so that he/she does not have to get used to some terms of NVDA.
It's a very special screen reader with a great number of features that I love and I regret the fact that it is not so much integrated in some areas where most of blind people have to work on.
Cheers!