Will a 650W PSU do?

I've built a new i7 rig (specs to the left) reusing a year old Corsair TX 650W from a previous build but I'm not sure if the PSU is suitable for my new machine.

Using a mains power meter I've maxed out the reading to 560W by running IntelBurn Test and Futuremark Vantage looping perlin noise which seems to be the most GPU intensive test. Playing games like Crysis or GTA4 pulls no more than 500W.

Am I right to assume the following:
The PSU is rated 650W and is at least 80% efficient, therefore running the PSU on a 100% load pulls 813W from the wall?

So, my rig pulling 560W from the wall is only using 70% (448W) of the TX's 650W capacity?

Since the max power draw of this rig is somewhat less than 650W and the normal draw is even less, I should be fine, right?

Oh, and what other tools can I use to totally max out the power consumption on my machine to be totally sure?

Thanks!

Sounds about right, most people over estimate the amount of power required to power there pc.

I've found both the atitool and furmark useful tools to load/burn test the gpu.

I would check the rail output when under load, make sure that's not dropping or becoming unstable, esp the +12v

I forgot about the rail voltages, thanks for reminding me. I was going to do this using my multimeter but I've accidentally fried the probes by leaving it on current mode across the mains when I intended to measure voltage, the probe leads totally melted!

EDIT: Ok, I've run furmark and intelburn test ticking all the boxes I can to maximise resource utilisation and managed to peak at 695W, which means the system only uses 85% of the PSUs capacity. 12v, 5v and 3.3V rails are stable too. Fans however are going berserk! The system is unlikely to reach that level of power consumption under normal use, looks like I can forget about that PSU upgrade and look forward to some new SSDs :D