PC133 DIMM's backward compatible with 66mhz bus?

[BaNdiTmaN]

Are PC133 DIMM's backward compatible with 66mhz bus?

 

[Dulanic]

Yes

 

[shawnmos]

I second that yes!

 

[BaNdiTmaN]

Thanks a lot Guys!!

 

[bacillus]

hmm,I guess he was asking because PC133 is more easily vailable than PC66!

 

[shawnmos]

Well if he gets PC133 he can upgrade his computer and he won't have to get new ram.

 

[ruckb]

Hi,

I do mainly aggree with the yes, but not so completly.

As the access time from clock was getting shorter for PC133, on bad designed PC66 Systems you can run into problems with the Hold time of the data (tOH).
If the system is strobing to late, then the data are not valid any more.

This is one think I can imagine what could happen. I'm sure, there are other things, but I expect this kind of stuff only for bad system design.

ruckb

 

[Wingznut]

Do you need another "Yes"?

 

[Vinny N]

Yes speedwise they should be unless you're looking at some stranger systems like a Compaq 4000S or a Gateway 2000, they may slightly disagree with the timings. I've seen some systems throw a fit at PC66 ram because the timing was slightly off from what it expected. But if you're trying it in a system that old, you might get a problem with density that is, if you buy a high density module like an 8 chip 128mbyte dimm, the system might read that as 16mbytes (2mbytes a chip, the max it understood at the time).

Give it a try though, it'll work right or it won't

 

[DaddyG]

I second the post by Vinny. PC66 never was a 'real' standard. Timing issues can be a problem BUT I think the density issue could be a bigger problem. Check out the chipset on your mobo, BX chipsets are a no-no with most high density DIMMS.

 

[redls1]

I have a question to ask also. Does it matter if the ram came from a server or not? I just purchased 128 kingston that came from a server and it doesnt even post. I am currently running 256 (2 *64) and (1* 128). The motherboard is a gigabytega-6vxe7. Thanks for any help.

 

[BaNdiTmaN]

I just wanted to get a couple of 128 sticks for my brother in law who has a Compaq 333. Hard to beat $90 for 256. It doesn't seem like that long ago when 128 was almost $200. Thanks for the info!

 

[MulLa]

I did have an experience where an old LX mainboard refused to recongnise 128MB of PC133 before. Never figured out why since that stick would work perfectly in a BX board.

 

[Dulanic]

<< I have a question to ask also. Does it matter if the ram came from a server or not? I just purchased 128 kingston that came from a server and it doesnt even post. I am currently running 256 (2 *64) and (1* 128). The motherboard is a gigabytega-6vxe7. Thanks for any help. >>

There is always a chance the server used ECC or Registered RAM... most PCs can use ECC, but very few use registered.

 

[BaNdiTmaN]

So how low do you think RAM prices will go?

 

[mschell]

Believe it or not I'm running a 128MB stick of Micron -7.5 in an old Tyan socket 7 MB. It was one of the first boards to support DIMM modules, they just called it SDRAM back then, it seemed very exotic until Tom tested it as compared to EDO SIMM memory commonly used at the time - it gave like a 2% performance boost - shades of the current DDR memory performance letdown.
By the way, I'm just using the Micron stick to get the system set up as I don't have any SIMM memory, I raided my old junkbox for parts to assemble a computer for a friends kids ages 9 and 10.
System specs:

Old ATX minitower
Win98
Tyan 1572 MB
Pentium 166 (not MMx)
WD 2.1 G
8X CDROM
ATI Expert 98 8MB
64MB ??? memory
15&quot; monitor with lots of greasy fingerprints on faceplate
Spill proof keyboard and disposable mouse

Do you think they will like it?? - M.

 

[Zap]

I can verify that sometimes PC133 won't work with older systems.

System #1
Gateway G6-333c
Don't remember much of this system (from a month ago), but I do remember that no PC100 or PC133 stick would work in it. Tried about 6-8 different sticks of different densities.

System #2
Compaq Presario 5452
Just worked on it today. Two PC133 64MB (NEC) and one PC133 128MB (Micron -75) would not POST in that system. All three chips verified good. The original RAM in that system is 64MB Micron PC100 (-8E) and works fine. Also tried an old 64MB stick of Micron -10 and a 64MB stick of Samsung GL (both PC100) and they both worked. BTW, this system would give a POST error whenever the amount of RAM changed. Stupid-a$$ Comcrap. Can't even make their BIOS just accept different amounts of memory without complaining.