[G4] G4 Dual 867 MDD RAM question

[Aaron]

I need more RAM for my G4 Dual 867 MDD, which presently has one 512MB PC2100 stick in it. (It came with two, but I took out a bad one and can't remember where I put it so I can exchange it! <:-| )

Anyway, I'm about to buy more RAM and, since I have a lot of store credit from Amazon, I'm thinking of buying at least two of the following:

"Kingston 512 MB 333 MHZ DDR-PC2700 DIMM CL2.5 PC Memory"  $44.77 each (including free shipping)

which is listed at <http://www.amazon.com/gp/product/B00006HVT4/>.

As an alternative, I'm also considering:

"Kingston 1GB DDR400 C3 KIF [sic!] OF 2 ( KVR400X64C3AK2/1G )" $106.99 for the pair

which is listed at <http://www.amazon.com/gp/product/B00009XFVN/>, with the following info:

"ValueRAM's KVR400X64C3AK2/1G is a kit of two 64M x 64-bit (512MB) CL3 DDR400 SDRAM (Synchronous DRAM) memory modules. Total kit capacity is 1GB (1024MB). The components on each module include sixteen 32M x 8-bit (8M x 8-bit x 4 Bank) DDR400 SDRAM in TSOP packages. Each 184-pin DIMM uses gold contact fingers and requires +2.6V"

1) Will either (or both) of these work in my machine?

2) Will I be able to continue using the PC2100 stick I already have along with these?

3) If they both will work, what reasons might there be for choosing the higher-priced ones ($106.99 vs. $89.54 for 1 GB)?

Any definite information or reasonably well-informed opinion would be appreciated. But time is of the essence. I'm going crazy trying to do video work on this machine with only 512 MB of RAM

 - Aaron