Member Avatar for albertop9

Hi,

I've got an old white box with an EliteGroup (ECS) K7S5A (Rev 3.X) motherboard, which has 4 memory banks: 2 for SDR SDRAM modules (168-pin) and 2 for DDR SDRAM modules (184-pin).

It supports non-ECC, unbuffered modules only, up to a total of 1GB. Currently has one 256MB SDRAM PC133 module in it and I want to add a new 512MB module.

The issue is that Crucial's System Scanner recommends me to upgrade through a choice of DDR modules, while Kingston's website states that "This board supports both DDR and SDRAM memory technologies. However, they cannot be mixed at the same time."

So I'm pretty confused! Any advice?

The pages related to my mainboard I've looked up:
Crucial:
Kingston:
(I've given up at trying to find info on ECS' own website.)

MANY thanks in advance to everyone who can help!

Alberto,
Spain

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Short answer: and are correct — the K7S5A is a hybrid board that contains both SDR and DDR slots, but the motherboard/chipset will only run one memory technology at a time. That is why Kingston’s warning is accurate and why a scanner that suggests DDR should be read as “what this board can use if you convert to DDR,” not as permission to mix both types together.

Why you cannot mix: SDR and DDR use different signalling, voltages and pinouts. The board’s memory circuitry selects one mode; populating both kinds at once will typically prevent a proper POST, cause modules to be ignored, or produce instability. Physically they look different (different notch positions), but the real limit is electrical/protocol incompatibility.

Practical options and a safe procedure:

  • Option A (cheapest, least work): stay with SDR. Buy a matching unbuffered, non‑ECC SDR PC133 module sized to your needs; mixing capacities on the same technology is usually fine (the system will run at the slowest timings).
  • Option B (better performance): convert to DDR — remove all SDR sticks and install DDR modules only. Use unbuffered, non‑ECC modules of the speeds the board supports and populate the DDR slots.
  • Installation checklist: power down and unplug, ground yourself, remove the opposite-type modules, install into the correct slots, boot to BIOS to confirm total RAM, then run a memory tester (Memtest86+) for a couple of passes. If memory isn’t detected, reseat modules, try one stick at a time, or clear CMOS.

Final notes: verify module voltage/type (unbuffered/non‑ECC), consult the motherboard silk‑screen/manual for slot order, and remember the board’s 1GB maximum when planning upgrades.

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Member Avatar for caperjack

Hello i would suggest you get 2 -512 sticks of ddr pc2700 ram .If all you can afford is one than by allmeans just get one ,but get ddr as it is faster than the older sdram.

Member Avatar for albertop9

Thanks for your input, caperjack!

So, in spite of Kingston's warning about not mixing the two types of memory on my mobo, you see no problem in doing so, then? Or am I missing something…?

I know DDR is faster, and I considered getting two 512 DDRs, but for the use I'm giving this box... I'd rather get just one - as long as it can work no-problem with that 256 SDRAM, that is.

Member Avatar for caperjack

Thanks for your input, caperjack!

So, in spite of Kingston's warning about not mixing the two types of memory on my mobo, you see no problem in doing so, then? Or am I missing something…?

I know DDR is faster, and I considered getting two 512 DDRs, but for the use I'm giving this box... I'd rather get just one - as long as it can work no-problem with that 256 SDRAM, that is.

no you can't mix them,one type or the other . as it clearly states in the link in you first post .

Member Avatar for albertop9

[...] as it clearly states in the link in you first post .

It does indeed. But the Crucial System Scanner detects my installed SDRAM and still suggests me DDRs to upgrade, and states nothing about not mixing types... So I'm still confused! Who should I listen to??

Kingston+caperjack VS. Crucial (?)

Sorry. I need consensus!

Member Avatar for caperjack

It does indeed. But the Crucial System Scanner detects my installed SDRAM and still suggests me DDRs to upgrade, and states nothing about not mixing types... So I'm still confused! Who should I listen to??

Kingston+caperjack VS. Crucial (?)

Sorry. I need consensus!

ok,lets put it this was sdram is old school ,and ddr pc2700 is old school now too,,but is newer than sdram ,so remove you sdram and install some ddr ram for better and faster ram!don't know how else to put it to you!!

Member Avatar for jfvalenti

Welcome to Crucial Technology's Expert Online. An Expert Online agent will join you in a moment... Please do not begin typing until you have been connected to an agent.
Hello, my name is Dan . How may I help you?
Joe Vlenti: i have a Elite Group (ECS) K7S5A (Rev 3.X) Motherboard
Joe Vlenti: your scander saids
Joe Vlenti: Maximum Memory Capacity: 1024MB
Currently Installed Memory: 256MB
Available Memory Slots: 1
Total Memory Slots: 2
Dual Channel Support: No
CPU Manufacturer: AuthenticAMD
CPU Family: AMD Athlon(tm) Processor Model 6, Stepping 2
CPU Speed: 1095 MHz
Joe Vlenti: i have 4 slots
Joe Vlenti: what to do?
Dan : Correct. This is a hybrid board. You only have two slots of each different memory, but you can only do one type at a time.
Joe Vlenti: ok, so what would you do?
Dan:

Member Avatar for albertop9

THANKS A LOT Joe !!

Funnily I never got to upgrade that PC back in the day of my post (over 2 years ago, man!) so your info comes in handy! Now you've reminded me about it, I'll try to do the upgrade asap so we squeeze some extra life from that old box.

Cheers!
A.
Spain

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