Moving but at a slower rate, but
it has a tendency to snarl up really easily, with accidents or similar, and then you can be stuck stationary for a long time. Also, as I'm sure you know, rush hour is always much worse on a Monday, compared with Tuesday onwards.
If you're willing to try a slightly different route (and have a sat-nav for emergency backup!), I'd potentially suggest taking this little detour
: leave the M40 at J4, and head south along the A404 and A404(M) (which can get quite busy around J8/9 of the M4, but not impassable. Then head along the A308(M) and then A308, and cut through Bray, Fifield, Windsor and Old Windsor, and on to Staines. That's the route (up to Windsor) that I take to work in the mornings if the M4 goes wrong, and I have to jump ship at J8/9 (I commute from Reading to Slough). It usually runs clear, and it'll save you M25 woes (just make sure you don't accidentally go on to the M4, which will also be dire).
Just an idea, works for me in the mornings, but I can't guarantee it'll work tomorrow