I’m upgrading the Laptop ram. Currently the slots are filled with two 256MB DDR 333mhz ram. I am planning to replace one 256MB with 1GB. My doubt is will the remaining 256MB ram contribute to my total memory. Is it advisable?

Answer:
Yes you’ll have a total of 1280MB of ram available. Also just check both are of the same type, DDR1, DDR2 etc and if the 1GB is rated faster than 333MHZ it will run at a slower speed of your 256MB's 333mhz.
Answer:
Yes, the remaining 256 will add to the 1 GB. However, DDR is quickly becoming an obsolete technology, so upgrading it might be a high-priced endeavor.

Make sure to find the correct model number for your personal, and then go to Crucial.com's memory finder tool, input the information it asks, and it'll give you a list of compatible RAM that’ll work with the personal.

Answer:
Sangeeth Jee, yes you can add in another 1GB RAM, but really there wont be any contribution by the 256MB RAM. And again if you want to add in another 1Gb RAM with 256MB, then you will have to search for a 1Gb RAM with 333MHz or else they wont work together, and finding a 333MHz RAM is quite difficult and will be pricey as well.

So its superior to remove both the RAMs, then check how much MHz of RAM your motherboard supports and purchase the 1Gb RAM accordingly.

Answer:
Can't get a difinitive answer without the make and model of the laptop. If it will be able to see all the memory, it's certainly going to give your notebook a nice boost. You can Add Detail to your question to let us know the make and model.
Answer:
That would depend on the motherboard design. Some require that the ram sticks come in pairs of same capacity while others don't. You will have to read the manual or do it by trial.
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yes it will but you may have some frequency mismatch and/or latency issues with two different sized RAM modules.
IMHO: purchase a new one! you just westing your time and money on this issue.
Hope it helps!
thnx!
Answer:
no get a new laptop you sound like you’ve an old personal so i would just et a new personal because you’ll have other problems with it soon
Answer:
probably not, if your laptop came with that little ram then it probably maxes out at 1g

check crucial.com to be sure

Answer:
Just try them together, if you get freezing or blue screens remove the 256Mb.