RAM: PC100/PC133?

[etalianstallion]

Okay, so I'm just too lazy to go surf and find the answer to my question, and since people using these forums are quite knowledgable and willing to help, I figured this is a good place to ask.

Anyway, I am running an old desktop at home, just a PIII 450. The home-built machine is almost 3 years old and still running fine, but I wanted to add some RAM to it. I am currently using PC100 SDRAM and wanted to know if I would be able to add in PC133 SDRAM.

Any help here would be appreciated. Thanks!

[ECOslin]

Likely not, PC133 ram is installable on many older motherboards, but, if the motherboard is unable to take advantage of the slight higher speed, the PC133 ram will only be used by the motherboard as if it were just PC100.

Edward

[mscdex]

If you could tell us what motherboard it is that you're using, we could help you determine that. :)

[TopDog]

You also need to consider the CPU rate... is it able to handle 133Mhz? If not, the RAM will go at 100Mhz...

[Janak Parekh]

In other words, there's a 99.99% chance PC133 memory will work just fine in your machine, but it will definitely not be "faster" than PC100 memory (except for the fact that you'll have more memory, of course) -- the PIII/450 uses a 100MHz FSB. :)

Since PC100 memory is effectively deprecated nowadays, getting PC133 would probably be the route to go. The real important thing is to make sure your mainboard can handle the capacity you want to add. A lot of older PIII mainboards have trouble with 512MB SDRAM DIMMs, and a few had trouble with 256MB.

--janak

[etalianstallion]

Thanks for everyone's help here. Just as an FYI, I am using an Asus P3B-F motherboard. I've been looking for PC100 memory but no one really carries it anymore, especially not past the 128MB size.

If I understand this correctly, it is that I can use/mix PC100 and PC133 memory without any problems. Sure, I won't get the PC133 performance, but all I am looking for is just more memory at this point. Frankly, I'm surprised that my computer has lasted me this long, although I am itching to jump in on one of those Dell Desktop or Server deals.

[etalianstallion]

DOH! I was going to pick up the PNY 256MB SDRAM PC133 (Sku=457395) from Staples and I saw the following "disclaimer":

Please Note PC133 memory modules are no longer compatible with PC100 machines.

PNY 256MB SDRAM PC133 (http://www.staples.com/Catalog/Browse/Sku.asp?PageType=1&Sku=457395)

Are there now even different types of PC133 SDRAM? Help!!!

[trachy]

Please Note PC133 memory modules are no longer compatible with PC100 machines.

Now, that sounds just plain stupid. The implication is that at one point in time they were compatible. What happened to them that made them all of a sudden incompatible? Did the Staples Sourcerer wave his wand one day and make it so?

[trachy]

Hey, man - you can get up to 256Mb DIMMs through Crucial. Check here (http://www.crucial.com/store/listparts.asp?Mfr%2BProductline=Asus%2B+Motherboards&mfr=Asus&cat=RAM&model=P3B-F&submit=Go).

[Janak Parekh]

Please Note PC133 memory modules are no longer compatible with PC100 machines.
Now, that sounds just plain stupid. The implication is that at one point in time they were compatible. What happened to them that made them all of a sudden incompatible? Did the Staples Sourcerer wave his wand one day and make it so?
Yeah, this is just plain weird. PC133 primarily defines stricter timings so the memory can operate faster, and I don't quite see how it wouldn't work in a PC100 mainboard... is it cheaper to build RAM that can't run slower!? That said, Crucial memory is very good, so I'd consider going with that anyway. :)

--janak

[trachy]

That said, Crucial memory is very good, so I'd consider going with that anyway. :)--janak

Yeah. I've ordered from them a few times and have nothing but great experiences. They're quick, cheap, and their consistently ranked in the top 5 at ResellerRatings.com.

The only negative thing I can say about them, is that they don't sell SD. I asked them about it a while back, and they indicated they didn't have any plans on getting into that market. :cry:

[Dave Beauvais]

... Please Note PC133 memory modules are no longer compatible with PC100 machines. ...
I've seen this in another "generic" brand sold at Micro Center (http://www.microcenter.com) stores. (I forget the brand name, but it begins with "B," if I recall correctly.) Basically, there is something in the SPD chip (Serial Presence Detect -- the chip that identifies the DIMM to the BIOS and tells what the chip is capable of doing) that indicates it will only operate at a 133 MHz bus speed. I can see no practical reason for doing this other than to force people to buy the now more expensive PC100 RAM if they can manage to find it anywhere.

It may be possible to run these PC133 DIMMs by going into the BIOS and configuring RAM timings manually, but this is a pain in the ass that you shouldn't have to deal with. I agree with other posters: buy Crucial (http://www.crucial.com).

--Dave