explaining on video card speed vs. the pixel pipe thing

okay, when it comes time to buy a video card, i need a little clarification on a few things. OKay say for instance im looking on newegg and Im comparing two video cards were runs at a 625mhz core clock speed , 1450 mhz memory speed , but only have 16 pixel pipelines and one that runs at a 450mhz core clock, with 1250 memory speed, but has 24 pixel pipelines, which do you chose. Can someone explain to me this whole pixel pipeline vs. a lower pixel pipeline card but with higher clock speed. If you had to chose from the 2 how do you know which one to go with, the one with lower clock speed but more pixel pipelines or visa versa. THanks.

as a general term more is better... but you cant compare apples to oranges in this situation IE you cant compare Nvidia to ATI when it comes to pipelines and clockspeed because they just dont perform the same. As of lately Ati has gone the way of efficiency while nvidia has gone the way of more pipelines. nvidia is now up to 24 pipelines per card with the 7900gx2 being an exception. Ati is still using 16 pipelines but the efficiency of its cards is insane. It helps to look at the numbering system, usually the higher the number the better the card hence 7900gt>7800gt | 7900gtx>7900gt |x900xtx>x1800xt. The higher end models for both companies end in some variation of 8xx or 9xx the middle line models end in 7xx or 6xx and the lower end models end in 2xx-5xx