upgrade to 512 mb ram but bios only sees 256

[trenchfoot]

tried to upgrade pc133 ram in a sony vaio pcv-rx260ds. says right on front of pc that it's upgradeable to 512.
128mb is loaded as shipped.
went for the memory upgrade to match os upgrade from win98se to winxp home.
checked with vendor that says only upgradeable to 512 using 2x256 sticks, so i went with that.
bios says sdram config is by spd, showing latency at 2t, ras-cas 2t, ras precharge 2t.
problem is with 512mb loaded, bios shows only 255.
removing one 256 stick with one 256 installed shows only 128mb.
re-installing the original 128 and a new 256 stick grossed out at 256 again.
switched slots with 128 and 256 sticks showed same 256 again.
in bios i switched ram config to user defined and optioned 3t latency across the board with no joy.
ran the sticks in another pc and came out with 512 as advertised.
next? 🙂

 

[Smithyoffline]

faulty ram? faulty motherboard? wrongly install? it is hard to tell

 

[Corporate Thug]

how many ram slots are there?

 

[imported_Phil]

It's the wrong speed. You're using PC133 and the laptop will want PC100. I see it all the time with Sonys.

 

[Jiggz]

Have yoou tried upgrading the bios yet? The only thing I can see that would indicate such a fault will be on outdated bios. At any rate, does the OS sees the entire 512mb or ram or just 256 as reported by the bios?😎

 

[imported_Phil]

In this case, an updated BIOS will do nothing for the problem. Believe me, I've been through this with countless machines. If he has PC133, he will need PC100.

 

[Arcanedeath]

You've prob. got high density memory and your system prob. needs low density, this is a common problem w/ older PC's, I'd suggest using crucial's memory selector or something similar to make sure you get memory that is compatible w/ your system. Hope this helps... 🙂

 

[DaveSimmons]

Too late now, but you should have gone to www.crucial.com and used their memoty selector. You'll need to return or eBay the high-density RAM and buy the right kind.

 

[trenchfoot]

'k guys, thanks for the input. nice knowing you guys are here with all this experience and knowledge and willing to help out. i'll get right on it and check back. thanks again. 🙂

 

[trenchfoot]

went online to crucial, found out the exact type of mem to get.
i had my vendor cross-reference the crucial part number, got them to agree to an exchange + some $. going from generic to simpletech brand. (i'd get crucial if i could, but not available locally and i need to get this box up and out of here soonest.)
i'm on my way out shortly to do the deed. thanks all. 🙂