Need to match new mobo with existing memory

[Thomasain]

OY there- I have 3 in-the-box DIMMS of 512M each, and am trying to figure out where I can find a vendor who has a decent list of "what memory goes with what motherboard" or whatever- I am not particularly hardware-savvy, but I can read compatability charts! I guess I'm doing this backward: usually you pick a motherboard/processor, then start filling it in with all the **** you fill it in with. I've got the ****, and need a better place to stick it. :)

What I've got: Kingston KVR266X64C25/512 (3 of them) which are 266MHz DDR (PC2100) running @2.5V. I want to bump up to an 800MHz FSB @ 3.0GHz or better, so I think I also have to ditch the P4 I have already- mine is a P4 running at like... 900MHz or 1.1GHz or something close to that, and my motherboard is a P4B. Is my thinking right? Is a P4 1.2GHz CPU a different entity than a P4 3.0? Or is it the same processor stuck on a different motherboard? I think they are two different animals- that's why I'm planning to go from my 300MHz FSB 900MHz P4 to an 800/3GHz P4. Right?

I found a site that had a great little search feature that allowed you to put in a memory type and it would display all of the motherboards that used that type, but that was 6 weeks ago and took 3 hours of bouncing around the net to find. Now I can't find it and I'm getting a headache.

I know the RAM I have isn't spectacular, but it IS brand new and totals 1.5GB, so why not match my new board to it, eh?

I'm not doing this on the cheap, but I don't want to throw away perfectly good RAM in favor of the latest, greatest, matched, same-lot-number stuff. I use this PC to play Dark Age of Camelot, and since the latest graphics engine upgrade we all need to bump our computer performance. This game responds well to more system RAM. That, and my video card fan has stopped running- if I spin it with a Q-tip it will make around 10 jerky revolutons, then stop. Video cards generally have a lifetime warranty, but it can take months to actually get the replacement (or that has been my experience so far anyway) so really the manufacturer's lifetime warranty is bogus- who can go 7 or 8 weeks with no video card? So I'm going to try to bag a new vid card too. Ick- I guess next I need to consider power supllies, eh?

[BipolarBill]

This is very simple - the PC2100 RAM cannot be used on anything faster than an Athlon running at 133MHz or a 533MHz P4. It is essentially 133MHz RAM. You will need DDR400/PC3200 for the P4"C".

[Peter M]

Not necessarily - most SiS and some VIA chipsets let you run the RAM bus at a slower or faster speed than the processor bus.

So although a P4 "C" flavor at FSB "800" (200 MHz QDR actually) won't be perfectly happy with RAM running at 133 MHz DDR (PC2100), it'll work.

The same applies for K7 and K8 platforms. The SiS chipsets let you run the RAM at any speed regardless of CPU speed (my ECS L7S7A2 board can go all the way down to 66 MHz for the RAM), and the Athlon 64's integrated RAM controller has the flexibility to do that as well.

The P4 is the processor platform the most dependent on fast RAM of those three, so for recycling your old RAM it is actually the worst choice.

I'd browse a few reviews of SiS and VIA chipset boards to see what speed options their BIOSes actually implement, and make the choice from there.

[causticVapor]

Yeah, see, that's the unfortunate thing - I'm sure he paid a pretty penny for those PC2100 dimms when he bought them. And he'd only be able to run two of them to allow for any kind of dual-channel feature to be implemented on a P4 board.

If it's decently new PC2100, and good quality, it might have a hance running at 333MHz. That would bottleneck a p4c far less.

That and a fourth RAM stick if he wants to use all three of the original DIMMs and not only two for DC functionality.

[causticVapor]

Extremist's advice: ram the vdimm up and loosen the timings tremendously to get the PC2100 to run at PC3200 speeds. I have my doubts about the PC2100 running at 200MHz with even remotely tight timings.


Since p4s benefit more from bandwidth than timings, you're in luck. If you were upgrading to an athlon xp or 64, the lax timings would really hurt.

[Sterling_Aug]

Sell the RAM on ebay.com and buy new.

[Yoshi]

Originally posted by Sterling_Aug
Sell the RAM on ebay.com and buy new.

Don't we all:D

[Peter M]

Originally posted by causticVapor
Yeah, see, that's the unfortunate thing - I'm sure he paid a pretty penny for those PC2100 dimms when he bought them. And he'd only be able to run two of them to allow for any kind of dual-channel feature to be implemented on a P4 board.

If it's decently new PC2100, and good quality, it might have a hance running at 333MHz. That would bottleneck a p4c far less.

That and a fourth RAM stick if he wants to use all three of the original DIMMs and not only two for DC functionality.

The plan is to just go for a single-channel board of your favorite kind (P4, Athlon, K8) that can run them at PC2100, sorted.

In contrast to what vapor said, I recommend going with AMD since these exactly _don't_ mind the lower RAM speed as much as a P4 does. Pentium-4 as its major design weakness lies in its huge performance penalty when encountering a pipeline stall, paired with really tiny L1 cache. Athlon and K8 don't mind slow RAM nearly as much.