So I did calculations with the Thermaltake Power Supply Calculator...

[Jawn]

http://www.thermaltake.outervision.com/Power

I'm currently running a 650W PSU.

Right now my specs are:
System Type: Quad Processor
Motherboard: High End - Desktop
CPU: Intel Core i7 920 2667 MHz Bloomfield
CPU Utilization (TDP): 85% TDP
RAM: 6 Sticks DDR3 SDRAM
Video Card: ATI Radeon HD 3870
Video Type: Single Card
SCSI HDD 10,000 rpm: 1 HDD
SATA HDD: 1 HDD
DVD-RW/DVD+RW Drive: 1 Drive
USB: 13 Devices
Regular: 6 Fans 120mm;
LED: 1 Fan 120mm;
Keyboard & Mouse (included):Yes

-------------------
When System Load is at: 90 %
Capacitor Aging (+ W %): 20 %

Recommended PSU Wattage: 784 Watts



I intended to buy a 4870 soon, if not 2, and OC my i7 to 3.6GHz and it gives me these specs:
System Type: Quad Processor
Motherboard: High End - Desktop
CPU: Intel Core i7 920 2667 MHz Bloomfield
Overclock: 3666 MHz, 1.2 V
CPU Utilization (TDP): 85% TDP
RAM: 6 Sticks DDR3 SDRAM
Video Card: ATI Radeon HD 4870
Video Type: Crossfire
SCSI HDD 10,000 rpm: 1 HDD
SATA HDD: 1 HDD
DVD-RW/DVD+RW Drive: 1 Drive
USB: 13 Devices
Regular: 6 Fans 120mm;
LED: 1 Fan 120mm;
Keyboard & Mouse (included): Yes
When System Load is at: 90 %
Capacitor Aging (+ W %): 20 %

Recommended PSU Wattage: 1099 Watts


Keep in mind that I'm a motion graphic artist and I also do 3D rendering. I haven't done much 3D lately but when I do my 8 cores are at 100% on my monitor.
So if I plan to make these mods in the near future, I'd have to get like a 1200W PSU? Really? Jesus christ.

 

[bomberboysk]

Wait, i know your problem. You have a single processor system, not quad. A quad processor system means FOUR i7 920's, for a total of 16 cores/32 threads

 

[Jawn]

Oh thank god. BRB recalculate.

 

[bomberboysk]

Oh thank god. BRB recalculate.

Yeah, you should be around 400W or so single card and 600W or so dual card i would imagine.

 

[Jawn]

I changed the load to 100% and it's only........

CPU Utilization (TDP): 100% TDP
When System Load is at: 100%
Recommended PSU Wattage: 731 Watts


That's more like it. This is with OC'd + 2x 4870's. So I'd be safe with a 800W I guess.

 

[bomberboysk]

I changed the load to 100% and it's only........

CPU Utilization (TDP): 100% TDP
When System Load is at: 100%
Recommended PSU Wattage: 731 Watts


That's more like it. This is with OC'd + 2x 4870's. So I'd be safe with a 800W I guess.

Yeah, a good 750W(corsair/pc power & cooling come to mind for good 750W psu's) or good 800W(Xclio stablepower, OCZ Game/Modxstream/Antec/FSP/Zalman come to mind for 800w) should power that just fine.

 

[Jawn]

Yeah I was eyeing the Modxstream for a while but it's only 700W.

Gamextream is 850W though.