Suppose I go out and buy a Compaq or HP computer and I want to upgrade the amount of RAM. Can I buy the ram anywhere or is there somethign about Compaq's RAM that will only work in their computers? Does anyone know how many memory slots their motherboards carry?

The compaq model I"m looking at comes with a standard 512MB. I'm guessing it's 2x256 since you can downgrade to 256, which is what I'm planning to do. Once I get the computer, I want to go out to the store and buy 2x512MB and stick it in there.

I would not suggest a store. Online configurators at Crucial, Kingston or Corsair will provide you with best matches and best prices on quality ram. Ram is one place where if you try to save a buck, you will most likely pay for it "with your shorts".
www.crucial.com
www.kingston.com
www.corsair.com
Go there now, put in the model you are looking at and checkout the answers.
If you have 2 256 sticks in and that would be unusual lately, and only 2 slots, you would need to get 2 512's to go to 1 gig and so on.
These prices are about 1/2 what Compaq or Dell would charge you.And if you are so inclined, you could recoup a ,ittle of your loss by selling the ram in the unit on eBay for $20 + freight on 256...remember it can be listed as new!

It's not economically viable to make propietry ram. The cost of developing and manufacturing such ram will significantly add to the retail price of the end product.

Rather than guess what type of ram they might put into the computer, why not make the salesman earn his commission/wages and ask them? Also ask them what it would cost to upgrade to 1GB ram. It would probably be cheaper than adding it later (they can get quantity discounts) and all of the waranty will be supplied by the one company.

"It would probably be cheaper than adding it later (they can get quantity discounts) and all of the waranty will be supplied by the one company."

Well they charge $100 to upgrade from 512 to 1024. And if I downgrade to 256, they subtract $40. I can find PNY 512 PC3200 DDR for $9 a stick. The cheapst Kingston I can find is $35.

Hi
personally id take a chance @
9$ a stick for pny or any 'other' brand is great news, as long as you not OC ing or using aggresive ram timings, its money in your pocket, i use any brand hynix,samsung, elixir mix n match whatever no problem just steer clear of 'no brand',tho OC ing is a no no use best rated.

Follow Rimfire's advice first and talk to the salesman. I learned my lesson many years back when I purchased my first PC....a Compaq. A mistake I'll never make again! At the time, their RAM was proprietary and knowing Compaq/HP the way I do, I'd wager they haven't changed. Back then, they put their parity chip on the RAM and not on the motherboard like everybody else. This forces the end user to buy their RAM (ie: more money in their pockets). At the time, that was an added expense of about $50.00 on a 4 MB SIMM. Total cost for the 4 MB SIMM was approx $250.00 (ain't it nice how cheap RAM is now!!!!)

Anyhow, if they're still doing things the same way, buying RAM without the parity chip on it and putting it in your system will cause you no end of hassles. So definately find out first before you even begin looking at what/where to buy.

Curt, I think you may have been wrongly informed about parity ram. I have never known it to be installed onto the motherboard. This would be the most expensive way of doing thins as the motherboard would have to be presupplied with ram chips to accommodate the maximum amount of ram the board could take. With 30 pin sims this was often 64MB which means 8 MB would have to be fitted to the motherboard just in case. This at a time when most computers ran 4MB!

In the early ninties, a major memory factory was destroyed during an earthquake. This at a time that windows 3.1 and the Intel 486 was making computers attractive for normal people led to ram being sold at around 80 USD per megabyte. This meant manufacturers could save around $50 by using non-parity ram and disabling parity checks in bios. Naturally many manufacturers did this.

By the mid 90s when prices had stabilised, it became a common practice to rip out the non-parity ram and replace it using parity ram. So, in the long run, the savings made were lost threefold.

For the sake of others, parity ram used nine chips in stead of eight. The ninth chip was used for a checksum which basically said the value of the byte was an odd or even number of 1s. This picked up the majority of memory errors.