RAM Latency

[Gilgamesh]

Been doing some reading up on RAM, was going to switch out my PC100 and up grade to DDR 2700,

I came across some articles that say that a pc133 with a CAS2.0 will run as well or better than DDR2700 with a CAS 2.5.

Of course a DDR2700 with CAS 2.0 is the best. but harder to find and more expensive.

Just wondering if anyone has had any "real life" experience with this, BTW my motherboard accepts both type memory.


Ill probably wait a couple months, the DDR2700 CAS 2.0 should be lower in price and more available. best i could find was 512 mb Corsair at about US$110 bucks. yeah i am on a budget.

[Trebor95]

pc133 is obsolete ram now, it is no where near as good as DDR.

you say that PC133 cas 2 is faster than DDR PC2700 Cas 2.5? that is not true at all.

there is not much difference between Cas 2.5 and 2 and it is not worth buying Cas2 as most stick of 2.5 rated ram will do Cas 2 anyway.

Also on your motherboard the fact that it supports both types means that it is an old motherboard and will probably not utilise PC2700 anyway, it'll probably only support 133Mhz FSB which equates to PC2100 anyway.

[OmnipotentKiwi]

DDR 2.5 over PC133 2.0 any day

[Gilgamesh]

I will still want to get that higher bandwidth, but getting a DDR "with" CAS 2.0 is got to be better than 2.5.

Here is the article i was writing about:

http://www6.tomshardware.com/motherboard/19980710/index.html

[Daleon]

DDR is better than PC133, period. You may not seem a huge difference right away but its there.

I always go for the best RAM I can get at the time, that way I don't have to upgrade it later. I went with Corsair XMS PC3500 cas2. This should last me through atleast one more chip/mb upgrade if not more.

High quality cas 2.5 DDR can run at 2.0, but not usually at its full speed or at its highest memory timings. Like if you got PC3200 cas 2.5, it may very well run at cas 2.0 at PC2700. But I doubt it will do 5-2-2-2. But you can pump more juice into memory also and get lucky. All depends on quality. Winbond chips are usually good and cheap, so memory using them may be what you want if you don't want high end corsair.

Also all this really only matters if memory speed/bandwidth if one of your current bottlenecks. If its not, you won't see a big difference. AMD's generally have worse memory bottlenecks. P4's have such higher fsb's that its not that big a deal. But you obviously have some kind of Thunderbird 1.0-1.3 or something where speed and memory are prolly bottlenecked.

[Ghoest9]

Dont read 5 year old articles when your trying to decide the best way to build a computer.

[SpacemanSpiff]

Just understand that most benchmarks will show that PC2700 RAM will actually run FASTER than PC3200. Go ahead and check it out at www.tomshardware.com - they explain the "why" in great detail. :thumbsup: