Member Avatar for mah300274

I have bought a lot of desktops and was looking around different sites for some of the computers. I came across and it has a picture (on page 51) and shows the ram slots but says DDR / DDR2, as if it were backward compatible? I know the 2 are not suppose to be in any way compatible or are there some types that are (this doesn't make sense to me as the voltage spike). Or is this an error?

The ram that was in it is a kt3g830-sa (512MB 168p PC133). But honestly I have not even tried to boot the computer as most in the lot have not been yet. But I was just curious about this.

Thanks!

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Short answer: that "DDR / DDR2" caption is almost certainly a brochure/diagram mistake. The Dimension 2400 is documented to use DDR (PC2100/PC2700) DDR‑SDRAM, not DDR2. (mail.jamesthompsononline.com)

Why it matters: DDR, DDR2 and older SDR (PC133) are mechanically and electrically different, so they are not interchangeable. Desktop DDR (often called DDR1) uses 184‑pin DIMMs and normally runs around 2.5 V; DDR2 uses 240 pins and ~1.8 V. Classic SDR PC133 modules use 168 pins and ~3.3 V. Each generation has the key/notch in a different place to prevent wrong insertion. For that reason you cannot plug DDR2 into a DDR socket (or a 168‑pin SDR stick into a DDR socket) without damaging the hardware. (crucial.com)

Practical checks to do before powering any machine from the lot: with the PC unplugged and you grounded, open the case and inspect the sticks and the slots. Look at the module label (it usually says PC133, PC2100, PC2700, PC3200, etc.), count the notches (SDR = two notches; DDR/DDR2 = one notch, but in different positions), and compare the stick size (168 vs 184 vs 240 contacts). Also verify the motherboard/model marking and cross‑check the official spec sheet before buying replacement RAM. Do not force a module into a slot. (oempcworld.com)

Bottom line: was right to call it a typo — but double‑check each chassis anyway. If you find 168‑pin PC133 sticks in a machine that the spec sheet lists as DDR, the modules probably belong to a different system or the wrong board was pictured; follow the identification steps above before attempting to boot or upgrade.

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Member Avatar for caperjack

hi, the ddr1 and ddr2 must be a typo ,as on page 70 in your link it states it takes sdram.
Maximum memory 2gig
Memory type PC2100 (266-MHz) or PC2700 (333-MHz) DDR-SDRAM (non-ECC)
and from my experience with Dells is will take nuthing faster that noted, like ddr-sdram 400.

all about ram types .
http://en.wikipedia.org/wiki/DDR_SDRAM

Edited by caperjack because: n/a
Member Avatar for mah300274

Ok, thanks for the reply. I did not notice / look at the specific specs. Amd thanks for the note as well.

Member Avatar for caperjack

your welcome,

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