These are 2.5v 820uF Chemi-Con solid polymer 8mm capacitors. They can be used to replace 6.3v 1500uF or 1800uF Electrolytic capacitors on vrm output and vdimm on GX motherboards. Poly caps are much more heat resistant, have a lower ESR, can handle a much higher ripple current, and have a longer life than wet caps. The polys have slightly thicker leads so you have to make sure the holes are cleared well, I use a stainless needle after clearing the hole. They fit with room to spare and will fall out when you flip the board if you don't bend the leads but they are a bit more time consuming to get on the board. On the plus side you will never have to replace them.
I uploaded some pictures of a Dell Optiplex GX-270 that I recapped with Polys
Nippon Chemi-Com Poly Application Notes