1) Memory compatibility does impact performance - but the change is sporadic. Generally, if you don't buy the memory that the mobo maker certified for it's boards - then you're on your own. But, folks like Crucial and Kingston have a very good gaurantee for their products that may make them worth trying for you.
2) Other memory - what's the return policy where you bought it? If you can return it - do so, based on the problems that you're having now. Is 7 out of 10 times good enough for you? It's not for me - I insist upon no errors with my RAM. You might try running this free, floppy based memory tester to see if there's a problem with the chip: http://www.simmtester.com/page/products/doc/docinfo.asp
Run it for at least 2 hours, but overnight is better - let us know if there's any errors.
3) Your fiancee doesn't want you to spend money on RAM? Are you sure that you've picked the right woman? Do you think that maybe you could trade her for the RAM? (just kidding!) Link to the Manly Man's Advice Column (it's a hoot!): http://www.bcsdesign.com/comedyzone/manly.shtml
Seriously tho', $240 for the 1 gB of the right RAM is way too steep! Crucial shows 1 gB of RAM for the Dell Dimension 3000 at $129!
1 gB of RAM will be plenty - but you'll get used to it quickly and will then tend to overload it with open apps, startups and extra services. This will necessitate even more RAM unless you're good about your housekeeping. If you're able to keep the clutter down, 1 gB will do you just fine. I've got 2 gB and leave everything open while playing FEAR and still get the occasional bit of lag (but when it's down to just 1 app - watch out!).
4) Can you use it in your Dell Dimension D333? I wasn't able to find this model on the Crucial site, but expect that since it's an older machine the memory won't be compatible.
But, it's easy to get an idea. First, look at your current RAM - notice about how many little gold fingers it has - do the slots on the old PC have about this many? Next, is the length of the chip the same length as the slot on the older motherboard? Finally, check the divots between the little gold fingers on the RAM - see where it's designed to fit only one way because of those "divots" - are they the same as the one's in the old PC's motherboard?
If that works - then check to see if the system is compatible with that type and size of RAM. Even if it's not the same brand that's "authorized" it may work (as long as it fits and is within the tolerances of the BIOS).
Edited by usasma, 13 March 2006 - 05:55 PM.