I have read a ton of research on google and found that the best option is from amazon.com
I also got very fast&free shipping from amazon for more than 50 usd items.

Corsair TWIN2X4096-6400C5C 4GB XMS2 PC2-6400 800MHz 240-pin Dual Channel DDR2 Desktop Memory

Tuesday, 09. March 2010. 23:54 by memory sdhc

Corsair TWIN2X4096-6400C5C 4GB XMS2 PC2-6400 800Mhz 240-pin Dual Channel DDR2 Desktop Memory List Price: $99.99
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The TWIN2X2048-6400C5 is a pair of 4 GB of DDR2 SDRAM DIMMs built using Corsair latest performance combined with high tech heat sink. This part delivers outstanding performance of the latest generation of dual-channel DDR2 motherboards like the nForce 780i chipset from NVIDIA. It has been tested extensively in most DDR2 motherboards to ensure compatibility and performance at rated speed. This memory has been verified to operate at 800MHz at low latency 5-5-5-end signature 18.Sporting sink Corsair patented heat-removing products IC XMS2 new feature dominant performance while promoting increased stability. It has been tested extensively in most DDR2 motherboards to ensure compatibility and performance at rated speed. Ask The RAM GuyCorsair has created a site 24 / 7 customer support online only for you to www.asktheramguy.com. Here you can find other people like you who are "in
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Corsair XMS2 4GB (2 x 2GB) PC2-6400 800MHz 240-pin DDR2 Dual-Channel Memory Kit – TWIN2X4096-6400C5

Sunday, 07. March 2010. 21:29 by memory sdhc

Corsair XMS2 4 GB (2 X 2 GB) PC2-6400 800 MHz 240-PIN DDR2 Dual-Channel Memory Kit - TWIN2X4096-6400C5 List Price: $87.99
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The TWIN2X4096-6400C5 G is a pair 4096MByte of DDR2 SDRAM DIMMs. This part delivers outstanding performance of the latest generation of dual-channel DDR2-based motherboards. It has been tested extensively in most DDR2 motherboards to ensure compatibility and performance at rated speed. This memory has been verified to operate at 800MHz at low latency of 5-5-5-18.
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CT25664AC800 Crucial Technology 2GB 200-pin DIMM DDR2 PC2-6400 Memory Module

Wednesday, 03. March 2010. 19:50 by memory sdhc

Crucial Technology CT25664AC800 2GB 200-pin SODIMM DDR2 PC2-6400 Memory Module List Price: $46.65
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Go faster and farther with a laptop or netbook Crucial memory upgrades. We SODIMM memory capacity for mobile systems. And as an extension of memory is one of the easiest, most convenient ways to improve system performance, is ideal for on-the-go users. When based on your notebook or netbook, counting on the Crucial memory. Crucial is a brand of Lexar Media family of products. So if you focus on your family, friends, work or life outside of work for DRAM products crucial to help make computing more reliable, faster and easier. With upgrades in nearly every PC and Mac here, the latest product and Solid State Flash Drive, you can be sure if it's important to you, is safe with us.
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