Will my psu do the job!
 

Ive had comp 2 years Evasham sli decimator its got a couple of 6800gts in,but now i want to change graphics cards for a 8800gt 512k,will my psu which is a tagen 420 watt be ok,later on in year ill get another 8800gt and then a new power supply!

Depends on what else you have in your PC, but I would probably say no it will not be ok. I have one 8800GTX and I use a 850watt PSU.

I have a 450W PSU for an 8800GT-512MB (overclocked), dual core at 4GHz, two hard drives in RAID 0, 2GB RAM, optical drive, two large case fans but not much else. The voltages stay up under load, nothing crashes unless I overclock too much, and it hasn't overheated yet.

I gather that the current capacity of the 12V rail(s) of your PSU is of importance.

should be fine, single graphics card and 420W is OK normally. Its a reasonable brand PSU, so there should be no over claims of its ability.

I'd guess that your CPU is around 110W, and the new card is about 140W. Thats 250W (or 20 amps) on the 12V rails.

2 8800s would be too much imo, 500W is the minimum and 600W to give a little headroom.

I agree with Luminous. It should be fine.

Total overkill then ;)

Unless you have server-like amounts of HDs I bet you never reach half that wattage under load, even with an overclocked quad core cpu.

Thank`s luminous and daz for reply`s.