question about memory upgrades

spooner_j

Hi all,

I was wondering if someone could help in answering this question for me...

Ive just ordered another gig of memory for my computer (2 x 512MB DIMMs), and the new RAM runs at 400Mhz. The thing is I just noticed that my current ram (2 x 256MB) only runs at 333Mhz, and I was told that if I add in the new with the old RAM the computer will run all of it at the lower of the two speeds...

What I was wondering is, would my PC run quicker overall with just 1 gig of 400 Mhz RAM or 1.5 gigs of RAM running at 333Mhz?

Any ideas?

Thanks!

unkel

spooner_j wrote:

I was told that if I add in the new with the old RAM the computer will run all of it at the lower of the two speeds...

You were told right

spooner_j wrote:

would my PC run quicker overall with just 1 gig of 400 Mhz RAM or 1.5 gigs of RAM running at 333Mhz?

Depends. What setup do you have, as in exactly what motherboard and cpu?

spooner_j

Thanks for the reply!

Not sure what motherboard it is. Its whatever one you get with a standard Dell. Its got a 2.8Ghz Pentium 4 though.

Ive just installed the extra gig alongside the existing memory and its not much faster really... The PC has 2 large hard drives though, both full of many many programs and files...

unkel

spooner_j wrote:

Not sure what motherboard it is. Its whatever one you get with a standard Dell. Its got a 2.8Ghz Pentium 4 though

It all depends what they are. I suspect the mobo and processor are 533FSB (133MHz quadpumped). In that case, both your old 333MHz and your new 400MHz ram will run at the same speed your old ram was running: only 266MHz :eek:

There is a slight possibility that your mobo and processor are 800FSB, in which case you should take out your old memory and stick in the new memory which will run at 400MHz, giving you a very, very substantial speed increase

Edit: is it a Dimension 4600 by any chance? I've just come across a Dell page where the 4600 with the 865 chipset was stocked with 2*256MB 333MHz ram and an 800FSB P4C 2.8. Shocking tbh why Dell allowed such a thing to be shipped :mad:

Good news for you if you've one of those. Take out the old ram and enjoy the speed

unkel

Here it is:

For $1,1291, the Dimension 4600 includes a 2.8 GHz Pentium 4 processor, 512 MB DDR-SDRAM memory at 333 MHz, a 60 GB hard drive, a 16X DVD drive, and 17" (16.0" viewable) CRT monitor.

spooner_j

Yeah its a Dimension 4600 alright. I'll open it up when I get home and check the motherboard, and if it is indeed the one you say I'll ditch the old RAM so.

Thanks for your help!

conzy

Dell use dividers to up the ram freqeuncy so usually on a P4 with a 133mhz fsb they use a 4:6 divider to run the ram at 200mhz (400mhz effective) I am not sure if you can change dividers in a dell bios, If not the new ddr400 ram will run at ddr333 and you just spent more on ram than you needed to:(

unkel

conzymaher wrote:

Dell use dividers

Yep hence my expression :mad:

Dividers and P4C do not go well together at all. At the time (we're talking about 2.5 - 3 years ago iirc) PC3200 was a bit more expensive than PC2700. Crap move from Dell to save a tiny amount of money to come up with this third class combination

conzymaher wrote:

I am not sure if you can change dividers in a dell bios

Neither am I, but it is likely one can

conzymaher wrote:

If not the new ddr400 ram will run at ddr333 and you just spent more on ram than you needed to:(

No, ddr400 ram is cheaper than ddr333 ram and has been for quite some time. If he had bought ddr333 ram, he would have spent more than he needed to

Worst case scenario for OP is that he now has 1.5GB instead of 0.5GB all running at the same speed of ddr333, as he had before the upgrade. Best case scenario is that he can take out his old ram, use his new ram 1:1 and enjoy a significant speed increase

SouperComputer

Dividers aside, the most likely scenario is that the BIOS will detect PC400 RAM through SPD and run it accordingly. BIOS update if available wouldnt do any harm.

Of course this is assuming you dont mix the 333 and 400 modules. Also noteworthy is that on some occasions a motherboards SPD may force the latency down on RAM if it its RAM bus is unable to run at the desired speed.

On a 2.8ghz CPU, the move from 333 to 400 is not significant IMO, but it never does any harm to keep em in sync.

conzy

But if he runs a 1:1 divider, the ram will only run at 133mhz which is only pc2100:(

But if he takes out the old ram and uses just the new ram with a 4:6 divider that will show the greatest performance IMO with 1gig running at ddr400 rather than 1.5gb running at ddr266

SouperComputer

But if he runs a 1:1 divider, the ram will only run at 133mhz which is only pc2100

In consumer motherboards SPD usually automagically takes care of this. Dividers are very seldom a user-configurable setting in such computers.