hi, im building a pc for internet and document uses,
i have this match
Foxconn A6VMX AM2+/AM2 AMD 690V Micro ATX AMD Motherboard
MSI R3450-TD256H Radeon HD 3450 256MB 64-bit GDDR2 PCI Express 2.0 x16 HDCP Ready Video Card
i have 250w psu from hp computer, only 1 year old, (1week used) it is in the box, sleeping
it doesnt have 24pin, only 20pin
i know 2600pro need 24pin, on mobo. when i tried it without 4 more pins, it does not turn on. (same psu 450W corsair)
will i be able to run this system??
total 240$

Motherboards are what require the 20 or 24 pins. I'm not sure I understand you, but each motherboard requires either 20 or 24 pins, and power supplies either have a 20 pin connector, a 24 pin connector, or a 20+4 connector (which will supply either kind). What graphics card you use has little to do with the 20/24 pin connector, that's a motherboard thing.

Video cards do often require a seperate connector, either a 4-pin molex, or a 6 pin PCI-e connector. I might be missing something, though. I'm not an expert on power.

i think you misunderstood me..
i had onboard graphics, which worked only with 20 pins, but, when i bought 2600pro, computer didnt turn on,
so i plugged 4 pin connecter for mobo, which makes 24pin. then it worked.

i meant, my psu only has 20 pin mobo, will it work to run 3450 with 20pin mobo?

i think 4 more pins are for graphics and pci cards..and more stuff on mobo.
this 3450 doesn require pci power pins.