Kingston PC133 SDRAM not backwards compatible?

[jrichrds]

Kingston states on theirValueRAM PC133 SDRAM page:
PC133 modules are NOT BACKWARD COMPATIBLE to PC100 machines
Systems using the 440BX, 810 or 810e chipsets should only use PC100 memory.

Are these memory modules different in some way so that it wouldn't work on motherboards with the chipsets listed above? I have 128MB PC133 PNY modules in my Asus P3B-F, and I thought as long as I didn't go past 256MB per module, I'd be fine.

One thing I noticed about the Kingston ValueRAM 128MB PC133 modules is that the chips are mounted horizontally rather than vertically. I couldn't see the whole module, but it looks to have 4 chips on one side.

Anyways, was just hoping to figure out what to look for if not all PC133 modules are backwards compatible.

 

[coolVariable]

Why should they be?

 

[Maggotry]

I ran into this problem shortly after they released that memory. At the time, they didn't have any disclaimer about that. I called them and what the tech told me (this was about 2 years ago so I don't remember verbatim) was that it had to do with the CL timings. Their value ram is pc133 cl=3. Going back to pc100 would slow the timings to "cl=4" which isn't possible. I'm sure some of the guru's here can explain it better, but basically, it's all about the timing.

The problem it caused me on an ASUS CUSL2 mobo, was that when ever you'd boot up, the pc would boot straight to the BIOS with an error sayng you need to check the fsb setting. It would only do it on a cold boot though. A warm boot would boot just fine. I experienced no other problem - just the cold boot error.

Kingston replaced the memory and sent me a grab bag of Kingston logo stuff including a very nice denim jacket, T-shirt, note pad, etc.

 

[Desslok]

I think it has to do with the BX and the 810 borads and not the mem. I remember reading something about it, let me look for it.

 

[Chang10is]

Yeah, I just found out the exact same thing a couple of days ago. I checked PNY's site, and their PC133 RAM is backwards compatible, so if you're buying RAM for a 100 MHz FSB machine, you might want to try to stick to PNY and other brands of RAM that are backwards compatible if you think you might want to move it to a 133 MHz FSB computer in the future.

 

[neoro]

I am Using a 440BX
Dell p2 450

I have
64MB SDRAM - From Dell
61MB SDRAM Kingston Value RAM-PC133
128MB SDRAM Kingston Value RAM-PC133

sure works fine for me........

 

[Codewiz]

It has nothing to do with timing or speed. It all has to do with the fact that they are HIGH DENSITY memory chips on the ram. BX boards can't recognize high density memory.

 

[jrichrds]

Originally posted by: Codewiz
It has nothing to do with timing or speed. It all has to do with the fact that they are HIGH DENSITY memory chips on the ram. BX boards can't recognize high density memory.

Makes sense. The 128MB PNY PC133 modules I have in my system have 8 chips each. The Kingston ValueRAM 128MB PC133 module I took a look at had only 4 chips.

 

[Maggotry]

Originally posted by: Codewiz
It has nothing to do with timing or speed. It all has to do with the fact that they are HIGH DENSITY memory chips on the ram. BX boards can't recognize high density memory.

Neoro already stated those modules work fine on his 440BX system. To confuse things a little more, I have an ABIT BX6 Rev.2 mobo with Crucial PC133 CL=2 high density modules on it and the system works fine.

So here's the summary:

A Kingston tech told me it's the CL timing.
Neoro says the Kingston modules work fine for him.
Codewiz says it's the density.
I use high density with a 440BX mobo and they work just fine.

Hope that clears it up for you, jrichrds. 😕