Hello I'm just wondering about RAM compatiblity in all and i have a question involving would it work to have 2x512MB DDR400 3200 NON-ECC 187 PIN SDRAM DIMM memory tossed in along with another 2x512Mb DDR266 184-pin PC2100 SDRAM DIMM.

When my Motherboard says it can support 4 RAM slots with DDR400/266 but the question remains.

OR if it will have any Problems what so ever

MotherBoard INFO
http://www.btecanada.com/catalog/product_info.php?cPath=66_121_145&products_id=2470

Model Sony Vaio PCV RX650
Board 845 Intel
CPU P4 1.6 Ghz
RAM 2x512mb PC2100 DDR 187PIN DIMM SDRAM NON-ECC
Graphics Adapter ATI
9800 256 Mb DDR SDRAM AGP 4X
Perament memory ATA/100 8

I don't think you have 187-pin RAM

As long as it's not a problem for you that all 4 sticks of RAM will have to run as PC2100 @ 133MHz, I guess you're OK. You may not be able to run in dual channel mode either...you won't know til you try

Asus A7N8X-X
1800+ @ 8.5 x 200MHz
768MB PC3200
Asus A9550 128MB/128-bit
Gamer Edition
WinME/WinXP Pro

http://www.asuscom.de/pub/ASUS/mb/socket939/A8V-E_Deluxe/e1781_a8v-e_deluxe.pdf

see page 35 - 36

Manual recommends DDR400 only. Whether you would get away with it I don't know.

Do you really need 2GB. For 'normal' computing you would be loosing performance.

WOOPS TYPO it's 184 pin sorry im going to wait for my pretty 40 pound box to come =)

Model Sony Vaio PCV RX650
Board 845 Intel
CPU P4 1.6 Ghz
RAM 2x512mb PC2100 DDR 187PIN DIMM SDRAM NON-ECC
Graphics Adapter ATI
9800 256 Mb DDR SDRAM AGP 4X
Perament memory ATA/100 8

Yes, it normally is possible to run different speed ram at the same time. The downside is that all of the ram will run at the speed of the slowest module. I doubt that the extra ram would improve the system speed more than the slower speed will hobble it.