RAM Upgrade

[Vortex187]

Okay, so I got 2 sticks of RAM for Christmas but they were completely the wrong ones.
They were CORSAIR 4GB(2 x 2GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) from newegg. Where my computer apparently requires DDR 400 (PC3200).

I as of right now have 1 gb of ram (2 of 4 slots filled) two 512's. I'm aiming for 3 or 4 gigs. Could someone help me in what to look for while buying RAM? Why some are more expensive than others of the apparent same quality. I'm looking for good speed/quality in games such as HL2, CS Source, Team fortress 2, WoW, Oblivion, and games soon to come out.

I appreciate the help ahead of time guys, thank you.

GPU: Radeon X1900 Pro
MOBO: Asus PTGD2-VX
Intel Pentium 4 CPU 3.60 GHz
Model: Sony Vaio VGC-RA828G(UC)

 

[Fat.Clown]

Why some are more expensive than others of the apparent same quality

Quotes of IceBlade008

If your system is designed for accepting DDR (Double Data Rate) memories of 184pin DIMM (usually desktops) or 200pin SODIMM (usually laptops) built, for your system to fully recognise 1GB capacity per memory slot, you need to use 'Low Density - 64Mx8 config' 1GB module. If you use 'High-Density - 128Mx4 config' 1GB module, your PC may only recognise it as HALF the size at 512MB or most of the time it will not work.
* All low density 1GB modules are made with 16 chips (8 chips on each side) using 64Mx8 device.
* All high density 1GB modules are made with 16 chips (8 chips on each side) using 128Mx4 device.

high density 1GB modules are mainly manufacturing process rejects/seconds that cannot be made as a low density modules. It is very much like Intel CPU, those CPU that cannot be made as Pentium 4 CPU become a slower bus Celeron CPU instead, by a down-binning process.

* LOW DENSITY modules have 100% compatibility with ALL systems and ALL chipsets.
* HIGH DENSITY modules only have 10% compatibility and are VERY SLOW.

Source:Info: What is the Difference Between Low Density and High Density RAM? - Overclock.net - Overclocking.net

Could someone help me in what to look for while buying RAM?

1.look for another 2 of 512mb sticks
(Q. why only 2 512mbs? A. because your computer only support up to TWO gigs)

2. make sure it is DDR, NOT DDR2

3. don't forget speed = DDR 400 (PC3200)

Edit:
Source:Sony VGC-RA828G Specifications

PS Welcome to Tech-Forums

 

[Vortex187]

I'm getting mixed messages =/, both

http://www.memory-up.com/Memory_Finders/DesktopSelector.aspx?ModelID=14333&system=1

and a diagnostic tool I downloaded (Belarc Advisor) Told me it supports up to 4 gigs, If these are wrong could someone link a reliable diagnostic sight? If I can only get up to 2 gigs I'm probably going to get a new motherboard...


Edit: Also, anyone familiar with newegg.com able to tell me where it differentiates between low and high density? Thanks