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PCI RAM Extender Cards?
stevejsmith asks: "I'm going to buy a Dell computer which supports DDR RAM, however it only comes with two DIMM slots. I have lying around two 128MB sticks of RAM, and want to use them. I know RAM is cheap, but I want some way to put more than two DIMMS in this system. Short of getting a new motherboard, is there any way I can add more RAM? On Slashdot I remember seeing a PCI card that help RAM for a RAM drive, but is there such thing as a PCI card that just held regular RAM for system usage? If not a PCI card, any other suggestions?"
Of all the things that a motherboard (or more specifically the collection of microchips known as the chipset) connects together the connection between the memory and the processor is the fastest the most important to performance. No other link, except between the processor and the motherboard even comes close in importance. Also, another issue that comes up is what is known as latency. Latency is the delay the system experiences when it requests memory access. It's not just how much data you can transfer, but how quickly you can have it after you ask.
For all those reasons it almost always makes sense, especially at today's prices, to have all the same memory modules in your system and the fastest memory your system can support. Even if you are able to recycle memory I would avoid doing so unless stability is an issue as many technical issues arise when DIMMS are mixed and matched.
The performance hit from this will negate any benefit you will get - you might as well just leave out the ram as it will be slowed down to PCI speed. As you said, RAM is cheap, so sell what you've got and buy one or two 512MB sticks.
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People have already mentioned its a bad idea. You may take them at their word, it is.
But that said, why even buy a system if it limits you before you have even opened the box? Ram is so cheap nowdays you have to be really stingy to not meet your base requirements, even if that includes a ton of Photoshop work, or most any other ram-intensive app. (Server stuff not withstanding.)
If possible, buy your Dell with minimum RAM posible, and buy 3rd party ram new to replace it, the largest size you can buy on a DIMM. That will give you 2x the maximum. If that isnt enough though, DONT BUY THAT SYSTEM! As for using the old ram, that will only slow your system down anyway. Deal with obsolescence and either reuse it in another system, sell it for a token sum, or give it away to someone who can use it. I tend to pass old hardware I have no need of anymore to friends or family.
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Bus RAM made sense on my 286 running windows 3.0. Real-mode paging was a real step up from the 1M memory limit.
Today it doesn't make any sense.
OTOH, the ram drive you mentioned might make sense (except that it is pretty expensive) if you used it for a swap partition.
I think that a better overall plan would be:
1. Don't buy a RAMBUS based system.
2. Buy one that supports an unreasonable amount of RAM, with only one slot populated with the largest module it supports. In a few years it won't seem like so much.
3. Reconsider buying a Dell. If you know how many DIMM sockets it has you aren't the target customer.
-Peter
it would be a decent solution because a RAM drive, while limited by the PCI bus would still be WAY faster as a swap drive than a hard drive.