RDRAM

[Cacolaco]

I am upgrading my computer on a very limited budget, and noticed that I could possibly use pc600 instead of pc800, which would mean the difference between upgrading to 768Mb instead of 512. Would I be better off sticking with less of the faster ram?

 

[Lord Evermore]

You should not reduce the speed of the memory in a computer, in most cases. If your computer uses single-channel RDRAM, you're already running at a disadvantage even with a 400MHz bus P4, because PC800 only provides half the memory bandwidth that a P4 needs with a 400MHz frontside bus. More memory can't make up for this extreme disadvantage.

If you have a dual-channel chipset (i850-class) then PC800 memory is just exactly enough to supply the P4 400MHz bus with enough memory bandwidth. Dropping to PC600 would make the system slower, and the extra memory would not make up for that. If you have a 533MHz bus P4, then even dual-channel PC800 is not enough to supply the processor, and PC600 dual-channel would provide only about 56% of the bandwidth that the processor wants.

In either case, 512MB of memory is enough for most applications, and reducing the speed in order to get more memory would result in a net loss of performance.

 

[Sunner]

Back in the day when Willy P4's and i850 were new, many sites benched them with PC600, PC700, and PC800 RAM, and PC600 caused a rather severe performance loss IIRC.

Of course nowhere near as bad as SDRAM did, but way more than you could ever make up by adding more RAM, unless you're running apps that really crave lots of RAM.

 

[AndyHui]

Originally posted by: Sunner
Back in the day when Willy P4's and i850 were new, many sites benched them with PC600, PC700, and PC800 RAM, and PC600 caused a rather severe performance loss IIRC.

Of course nowhere near as bad as SDRAM did, but way more than you could ever make up by adding more RAM, unless you're running apps that really crave lots of RAM.

That's right. PC600 performance is quite poor in comparison with PC800 RDRAM. You also need to remember that as RDRAM frequency increases, the latency decreases....so you are going to end up with even slower results than what is attributable to clock speed alone.

 

[Cacolaco]

Here's another question then....(perhaps a rather stupid one) I have the 850 chipset, but I can't figure out what kind of ram Dell put in my computer (dual channel or not). Is it going to cause any issues (other than a slower computer) if I put in single channel rdram? I seem to be having trouble locating pc800 dual channel.

 

[Lord Evermore]

If you have two modules, you're running in dual-channel mode. Dual-channel memory is done by having two modules installed, and is automatically enabled. Single-channel only happens if you put in an odd number of modules, or if the modules are not of the same type. It will cause SEVERE performance drops if you went to single-channel mode, even if you used PC800.

 

[FishTankX]

Cacolaco.

I believe the i850 is incapable of operating in single channel mode.

What you'll have to do, is purchase 2 sticks of PC800 and put them in your computer.

 

[HappyGamer2]

Cacolaco go here and look up your model it will tell ya what ram you have
http://www.crucial.com/index.asp?SiteID=AD

 

[JackBurton]

No matter if you have a Dell or a Compaq, an i850 is a dual channel chipset period. You'll need to install your memory in pairs.

 

[loafbred]

I recently added 256MB to my friend's Gateway i850 P4 Willamette 1.9. I was advised by a genuine RAM expert (over at Lost Circuits) to get the cheapest 16 bit PC800 I could find. My understanding is that each rimm of a pair needs to be identical to be stable, but each pair can be different brand. I got two 128MB rimms of Kingston, and it's been problem-free.