upgrading to 2 gb--2 pairs of 512 or 1 pair of 1 gb?

[sigpop]

which is more desirable? i have a dell 8400 with 2x512 mb. should i just buy another pair of 512 sticks or should i buy 2x1 gb sticks and ebay my existing?

 

[CalvinHobbs]

2 x 1gigs

 

[suszterpatt]

2x1GB. Some mobos/CPUs can't run 4 sticks at top speeds.

 

[poisonthewell]

another vote for 2x1gb; sell the ram you have to offset the price of the new sticks